Granît cureyekî kevirê magmatîk e ku ji ber hêz, tîrbûn, domdarî û berxwedana xwe ya li hember korozyonê tê derxistin. Lê granît di heman demê de piralî ye - ew ne tenê ji bo çargoşe û çarçikan e! Bi rastî, em bi bawerî bi pêkhateyên granîtê yên ku bi şekil, goşe û xêzên hemî cûreyan hatine çêkirin bi rêkûpêk dixebitin - bi encamên pir baş.
Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:
■ makînekirî
■ Dema ku tê birîn û qedandin bi rastî jî rast e
■ li hember zengarê berxwedêr
■ domdar
■ mayînde
Parçeyên granit jî paqijkirina wan hêsan e. Dema ku hûn sêwiranên xwerû diafirînin, ji bo feydeyên wê yên bilind, pê ewle bin ku granit hilbijêrin.

STANDARD / SERLÊDANÊN BILIND
Granîta ku ji hêla ZHHIMG ve ji bo hilberên me yên plakaya rûberî ya standard tê bikar anîn xwedî rêjeyek bilind a quartzê ye, ku berxwedanek mezintir li hember aşin û zirarê peyda dike. Rengên me yên Reş ên Bilind rêjeyên kêm ên vegirtina avê hene, ku îhtîmala ku pîvanên we yên rast dema ku li ser plakayan têne danîn zeng bibin kêm dike. Rengên granîtê yên ku ji hêla ZHHIMG ve têne pêşkêş kirin dibin sedema kêmtir tîrêjê, ku tê vê wateyê ku ji bo kesên ku plakayan bikar tînin westandina çavan kêmtir e. Me celebên granîtên xwe bi berçavgirtina berfirehbûna germî hilbijartin da ku em vê alî kêm bikin.

CUSTOM APPLICATIONS
Dema ku serîlêdana we plakaya bi şeklên xwerû, têketinên bi têl, qul an makînekirina din hewce dike, hûn ê bixwazin materyalek mîna Black Jinan Black hilbijêrin. Ev materyalê xwezayî hişkbûnek bilind, şilkirina lerzînê ya hêja, û makînekirina çêtir pêşkêşî dike.

Girîng e ku were zanîn ku reng bi tena serê xwe nîşana taybetmendiyên fîzîkî yên kevir nîne. Bi gelemperî, rengê granît rasterast bi hebûn an nebûna mîneralan ve girêdayî ye, ku dibe ku bandorek li ser taybetmendiyên ku materyalê plakaya rûberê baş çêdikin neke. Granîtên pembe, gewr û reş hene ku ji bo plakayên rûberê pir baş in, û her weha granîtên reş, gewr û pembe hene ku bi tevahî ji bo sepanên rast ne guncaw in. Taybetmendiyên krîtîk ên granît, ji ber ku ew bi karanîna wê wekî materyalê plakaya rûberê ve girêdayî ne, ti eleqeya wan bi reng re tune ne, û ev in:
■ Hişkbûn (xwarbûn di bin barê de - ji hêla Modulus of Elasticity ve tê nîşandan)
■ Hişkbûn
■ Tîrbûn
■ Berxwedana lixwekirinê
■ Îstîqrar
■ Porozîtî

Me gelek materyalên granît ceribandin û van materyalan berawird kirin. Di dawiyê de em gihîştin wê encamê ku granît reş ê Jinan çêtirîn materyal e ku me heta niha nas kiriye. Granîta reş a Hindî û granît Afrîkaya Başûr dişibin Granîta Reş a Jinan, lê taybetmendiyên wan ên fîzîkî ji Granîta Reş a Jinan kêmtir in. ZHHIMG dê li cîhanê li materyalên granît ên bêtir bigere û taybetmendiyên wan ên fîzîkî berawird bike.

Ji bo bêtir agahdarî li ser granîta ku ji bo projeya we guncaw e, ji kerema xwe bi me re têkilî daynin.info@zhhimg.com.

Hilberînerên cuda standardên cuda bi kar tînin. Li cîhanê gelek standard hene.
Standarda DIN, ASME B89.3.7-2013 an Taybetmendiya Federal GGG-P-463c (Plaqeyên Rûyê Granîtê) û hwd. wekî bingehek ji bo taybetmendiyên wan têne bikar anîn.

Û em dikarin li gorî hewcedariyên we plakaya teftîşa rastîn a granît çêbikin. Ger hûn dixwazin bêtir agahdarî li ser standardên din bizanibin, bi xêr hatin ku bi me re têkilî daynin.

Rastbûn dikare wekî hemû xalên li ser rûyê erdê di nav du balafirên paralel de, balafira bingehîn û balafira banê, were hesibandin. Pîvana dûrahiya di navbera balafiran de rastbûna giştî ya rûyê ye. Ev pîvana rastbûnê bi gelemperî toleransê hildigire û dibe ku destnîşankirina pileyê jî di nav xwe de bigire.

Bo nimûne, toleransên rûtbûnê ji bo sê pileyên standard di taybetmendiya federal de wekî ku bi formula jêrîn ve hatî destnîşankirin têne destnîşankirin:
■ Asta Laboratuarê AA = (40 + çargoşeyî/25) x .000001" (yekalî)
■ Asta Teftîşê A = Asta Laboratuwarê AA x 2
■ Odeya Amûran Asta B = Asta Laboratuwarê AA x 4.

Ji bo plakayên rûberî yên bi mezinahiya standard, em toleransên rûberîbûnê yên ku ji pêdiviyên vê taybetmendiyê derbas dibin garantî dikin. Ji bilî rûberîbûnê, ASME B89.3.7-2013 & Taybetmendiya Federal GGG-P-463c mijarên wekî: rastbûna pîvandina dubare, taybetmendiyên materyalê yên granîtên plakaya rûberî, qedandina rûberî, cîhê xala piştgirîyê, hişkbûn, rêbazên qebûlkirî yên vekolînê, sazkirina têketinên bi têl, û hwd. çareser dikin.

Plaqeyên rûyê granît û plakeyên teftîşa granît ên ZHHIMG hemû pêdiviyên ku di vê taybetmendiyê de hatine destnîşankirin pêk tînin an jî ji wan derbas dibin. Niha, ji bo plakeyên goşeya granît, paralel, an çargoşeyên sereke taybetmendiyek diyarker tune.

Û hûn dikarin formulên ji bo standardên din li bibîninDAKÊŞIN.

Pêşî, girîng e ku plakaya paqij were parastin. Toza aşındêr a hewayî bi gelemperî çavkaniya herî mezin a xirabûn û şikestinê ya li ser plakayê ye, ji ber ku ew meyla xwe dide ku di perçeyên kar û rûyên têkiliyê yên pîvanan de bicive. Ya duyemîn, plakaya xwe veşêrin da ku wê ji toz û zirarê biparêzin. Temenê xirabûnê dikare bi nixumandina plakayê dema ku nayê bikar anîn, bi zivirandina plakayê dem bi dem da ku deverek zêde neyê bikar anîn, û bi guheztina pêlavên têkiliyê yên pola yên li ser pîvanê bi pêlavên karbîd were dirêj kirin. Her weha, ji danîna xwarin an vexwarinên nerm li ser plakayê dûr bisekinin. Bala xwe bidinê ku gelek vexwarinên nerm asîda karbonîk an fosforîk dihewînin, ku dikare mîneralên nermtir bihelîne û qulên piçûk li ser rûyê bihêle.

Ev girêdayî ye ka tabaq çawa tê bikaranîn. Heke gengaz be, em pêşniyar dikin ku tabaq di destpêka rojê de (an jî di şifta kar de) û dîsa di dawiyê de were paqijkirin. Ger tabaq qirêj bibe, nemaze bi şilavên rûn an jî zeliqok, divê ew tavilê were paqijkirin.

Plaqeyê bi rêkûpêk bi şilek an jî paqijkera plakaya rûberê ya ZHHIMG Waterless paqij bikin. Hilbijartina çareseriyên paqijkirinê girîng e. Ger çareserkerek firar were bikar anîn (aseton, ziravkerê lakê, alkol, hwd.), buharbûn dê rûyê wê sar bike û xirab bike. Di vê rewşê de, pêdivî ye ku berî karanînê bihêlin ku plake normal bibe, an na dê xeletiyên pîvandinê çêbibin.

Dema ku ji bo normalîzekirina plakayê hewce dike, li gorî mezinahiya plakayê û rêjeya sarkirinê diguhere. Ji bo plakayên biçûktir divê saetek bes be. Ji bo plakayên mezintir dibe ku du saet hewce bin. Ger paqijkerek li ser bingeha avê were bikar anîn, dê hin sarbûna buharê jî çêbibe.

Herwiha plakaya avê diparêze, û ev yek dikare bibe sedema zengarbûna perçeyên metalî yên ku bi rûyê re di têkiliyê de ne. Hin paqijker piştî zuwabûnê jî bermahiyek zeliqok dihêlin, ku toza hewayê dikişîne û di rastiyê de aşînbûnê zêde dike, li şûna ku kêm bike.

Ev bi karanîna plakeyê û jîngehê ve girêdayî ye. Em pêşniyar dikin ku plakaya nû an aksesûara granîtê ya rastîn di nav salekê de piştî kirînê ji nû ve kalibrasyonek tevahî werbigire. Ger plakaya rûyê granîtê pir were bikar anîn, dibe ku were pêşniyar kirin ku ev navberê bo şeş mehan were kurt kirin. Kontrolkirina mehane ji bo xeletiyên pîvandina dubare bi karanîna asta Elektronîkî, an amûrek wekhev, dê her xalên aşîn ên pêşkeftî nîşan bide û tenê çend hûrdeman digire ku were kirin. Piştî ku encamên ji nû ve kalibrasyona yekem têne destnîşankirin, navberê kalibrasyonê dikare li gorî destûr an hewcedariya pergala kalîteya weya navxweyî were dirêj kirin an kurt kirin.

Em dikarin xizmetê pêşkêş bikin da ku ji we re bibin alîkar ku hûn plakaya rûyê granît a xwe kontrol bikin û kalibr bikin.

Gelek sedemên muhtemel ji bo cûdahiyên di navbera kalibrasyonan de hene:

• Berî kalibrkirinê rû bi çareseriyeke germ an sar hate şuştin, û ji bo normalîzekirinê dem têra xwe nehat dayîn.
• Plaqe bi awayekî nerast hatiye piştgirîkirin
• Guherîna germahiyê
• Pêşnûme
• Tîrêjên rojê yên rasterast an germahiya din a tîrêjkirî li ser rûyê plakeyê. Piştrast bin ku ronahiya serî rûyê germ nake.
• Guhertinên di gradyana germahiya vertîkal de di navbera zivistan û havînê de (Heke gengaz be, di dema ku kalibrasyon tê kirin de germahiya gradyana vertîkal bizanin.)
• Piştî barkirinê dem ji bo normalîzekirina plakeyê nehat dayîn
• Bikaranîna nerast a alavên teftîşê an karanîna alavên ne-kalîbrkirî
• Guhertina rûberê ji ber lixwekirinê

Çend celeb kun li ser granîta rasteqîn hene?

Qulfên li ser Pêkhateyên Granîtê yên Precision

Ji bo gelek kargeh, odeyên vekolînê û laboratuwaran, plakayên rûyê granîtê yên rastîn wekî bingeha pîvandina rast têne bikar anîn. Ji ber ku her pîvandina xêzikî bi rûyek referansê ya rast ve girêdayî ye ku pîvanên dawîn jê têne girtin, plakayên rûyê ji bo vekolîna kar û nexşeya berî makînekirinê çêtirîn asta referansê peyda dikin. Ew di heman demê de bingehên îdeal in ji bo pîvandina bilindahiyê û pîvandina rûyên. Wekî din, pileya bilind a rûtbûnê, aramiyê, kalîteya giştî û karê wan dike hilbijartinek baş ji bo sazkirina pergalên pîvandina mekanîkî, elektronîkî û optîkî yên sofîstîke. Ji bo her yek ji van pêvajoyên pîvandinê, pêdivî ye ku plakayên rûyê kalibrkirî bimînin.

Repeat Measurements and Flatness

Hem pîvandina rûberê û hem jî pîvandina dubare ji bo misogerkirina rûberek rast girîng in. Rûber dikare wekî hemî xalên li ser rûberê di nav du rûberên paralel de, rûbera bingehîn û rûbera banê, were hesibandin. Pîvana dûrahiya di navbera rûberan de rûbera giştî ye. Ev pîvandina rûberê bi gelemperî toleransê hildigire û dibe ku destnîşankirina pileyê jî di nav xwe de bigire.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:

Standarda DIN, Standarda GB, Standarda ASME, standarda JJS... welatekî cuda bi standarteke cuda...

Agahiyên bêhtir li ser standard.

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

Ji bo ku pelika rûberê hem taybetmendiyên pîvandina rastbûnê û hem jî yên pîvandina dubare bicîh bîne, hilberînerên pelikên rûbera granît divê Taybetmendiya Federal GGG-P-463c wekî bingehek ji bo taybetmendiyên xwe bikar bînin. Ev standard rastbûna pîvandina dubare, taybetmendiyên materyalê yên pelika rûbera granît, qedandina rûberê, cîhê xala piştgirîyê, hişkbûn, rêbazên qebûlkirî yên vekolînê û sazkirina pêvekên bi têl destnîşan dike.

Checking Plate Accuracy

Bi şopandina çend rêbernameyên hêsan, veberhênanek di plakaya rûyê granît de divê gelek salan bidome. Li gorî karanîna plakayê, jîngeha dikanê û rastbûna pêwîst, pirbûna kontrolkirina rastbûna plakaya rûyê diguhere. Qaîdeyek giştî ev e ku plakaya nû di nav salekê de piştî kirînê ji nû ve kalibrasyonek tevahî werbigire. Ger plaka pir caran were bikar anîn, tê pêşniyar kirin ku ev navberê kurt bikin şeş mehan.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations

Di hin rewşan de, di navbera kalibrkirinên plakaya rûyê de cûdahî hene. Carinan faktorên wekî guherîna rûyê ji ber xirabûnê, karanîna xelet a alavên vekolînê an karanîna alavên nekalibrkirî dikarin van cûdahiyan rave bikin. Lêbelê, du faktorên herî gelemperî germahî û piştgirî ne.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Extend Plate Life

Şopandina çend rênimayiyan dê li ser plakaya rûyê granît aşîbûnê kêm bike û di dawiyê de, temenê wê dirêj bike.

Pêşî, girîng e ku plakaya paqij were hiştin. Toza aşındêr a hewayî bi gelemperî çavkaniya herî mezin a xirabûn û şikestina li ser plakayê ye, ji ber ku ew meyla xwe dide ser perçeyên kar û rûyên têkiliyê yên pîvanan.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Plaqeyê dem bi dem bizivirînin da ku yek deverek zêde neyê bikar anîn. Her wiha, tê pêşniyar kirin ku balîfên têkiliyê yên pola yên li ser pîvandinê bi balîfên karbîd werin guhertin.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap

Dema ku pêdivî bi ji nû ve rûpûşkirina plakaya granît hebe, bifikirin ka ev xizmet li cihê kargehê an li tesîsa kalibrkirinê were kirin. Her tim çêtir e ku plaka li kargehê an li tesîseke taybet ji nû ve were pêçandin. Lêbelê, heke plaka pir xirab neçe, bi gelemperî di nav 0.001 înç de ji toleransa pêwîst, ew dikare li cihê kargehê ji nû ve were pêçandin. Heke plakayek heta wê astê çewtiye ku ji toleransê ji 0.001 înç zêdetir derkeve, an jî heke ew bi awayekî xirab qul an jî birîn be, wê hingê divê ew berî ji nû ve pêçandinê ji bo hûrkirinê ji kargehê re were şandin.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Divê di hilbijartina teknîsyenek kalibrasyon û ji nû ve çêkirina rûberê li cihê kar de gelek baldar be. Ji bo akredîtasyonê bipirsin û piştrast bikin ku alavên ku teknîsyen dê bikar bîne xwedî kalibrasyonek şopîner in. Tecrube jî faktorek girîng e, ji ber ku fêrbûna ka meriv çawa granîtê bi awayekî rast dipêçe gelek salan digire.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.Q

Checklist for Calibration Variations

1. Berî kalibrkirinê rû bi çareseriyeke germ an sar hat şuştin û ji bo normalîzekirinê dem têrê nekir.

2. Pêlav bi awayekî nerast hatiye piştgirîkirin.

3. Guherîna germahiyê.

4. Reşnivîs.

5. Tîrêjên rojê yên rasterast an germahiyên din ên tîrêjkirî li ser rûyê plakayê. Piştrast bin ku ronahiya serî rûyê germ nake.

6. Guhertinên di gradyana germahiya vertîkal de di navbera zivistan û havînê de. Heke mimkun be, di dema ku kalibrkirin tê kirin de germahiya gradyana vertîkal bizanibin.

7. Piştî barkirinê, dem ji bo normalîzekirina plakayê nehat dayîn.

8. Bikaranîna nerast a alavên teftîşê an jî bikaranîna alavên nekalîbrkirî.

9. Guherîna rûberê ji ber xişandinê.

Tech Tips

• Ji ber ku her pîvandina xêzikî bi rûyek referansê ya rast ve girêdayî ye ku pîvanên dawîn jê têne girtin, plakayên rûberê ji bo vekolîna kar û nexşeyê berî makînekirinê çêtirîn rûbera referansê peyda dikin.
• Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.
• Bernameyeke teftîşê ya bi bandor divê kontrolên birêkûpêk bi otokolîmatorekê ve di nav xwe de bigire, ku kalibrasyona rastîn a rûbera giştî ya ku dikare bigihêje Desteya Teftîşa Neteweyî peyda bike.

Di nav perçeyên mîneral ên ku granîtê pêk tînin de, ji %90 zêdetir feldspar û kuartz in, ku feldspar herî zêde ye. Feldspar bi gelemperî spî, gewr û sor-goştî ye, û kuartz bi piranî bêreng an gewr-spî ye, ku rengê bingehîn ê granîtê pêk tîne. Feldspar û kuartz mîneralên hişk in, û bi kêrê pola zehmet e ku meriv wan biguhezîne. Di derbarê xalên tarî yên di granîtê de, bi piranî mîkaya reş, hin mîneralên din jî hene. Her çend biyotît nisbeten nerm be jî, şiyana wê ya li hember stresê ne qels e, û di heman demê de di granîtê de mîqdarek piçûk heye, pir caran kêmtir ji %10%. Ev rewşa materyalê ye ku granît bi taybetî tê de xurt e.

Sedemeke din a bihêzbûna granîtê ew e ku perçeyên wê yên mîneral bi hev ve girêdayî ne û di nav hev de ne. Kun pir caran ji %1ê qebareya giştî ya kevir kêmtir pêk tînin. Ev yek dihêle ku granît li hember zextên bihêz li ber xwe bide û şilbûn bi hêsanî derbas nabe.

Pêkhateyên granît ji kevir tên çêkirin, bêyî ku zengar, asîd û alkalî li ber xwe bidin, li hember aşitiyê berxwedêr bin û temenê xizmetê dirêj bikin, lênêrînek taybetî tune. Pêkhateyên rastbûna granît bi piranî di amûrên pîşesaziya makîneyan de têne bikar anîn. Ji ber vê yekê, jê re pêkhateyên rastbûna granît an jî pêkhateyên granît tê gotin. Taybetmendiyên pêkhateyên rastbûna granît bi bingehîn wekî yên platformên granît in. Pêşgotinek li ser amûrkirin û pîvandina pêkhateyên rastbûna granît: Makînekirina rastbûn û teknolojiya mîkromakînekirinê rêyên pêşkeftina girîng ên pîşesaziya çêkirina makîneyan in, û ew bûne nîşaneyek girîng ji bo pîvandina asta teknolojiya bilind. Pêşveçûna teknolojiya pêşkeftî û pîşesaziya parastinê ji makîneya rastbûn û teknolojiya mîkromakînekirinê veqetandî ye. Pêkhateyên granît dikarin di pîvandinê de bi nermî werin şemitandin, bêyî ku rawestin. Pîvandina rûyê kar, xêzikên giştî bandorê li rastbûna pîvandinê nakin. Pêdivî ye ku pêkhateyên granît li gorî hewcedariyên aliyê daxwazê ​​​​werin sêwirandin û hilberandin.

Qada serîlêdanê:

Her wekî ku em hemî dizanin, bêtir û bêtir makîne û alav pêkhateyên granîtê yên rastîn hildibijêrin.

Pêkhateyên granit ji bo tevgera dînamîk, motorên xêzikî, cmm, cnc, makîneya lazerê têne bikar anîn ...

ji bo bêtir agahdarî bi xêr hatin ku hûn bi me re têkilî daynin.

Amûrên pîvandina granît û pêkhateyên mekanîkî yên granît ji granîteke reş a Jinan a bi kalîte bilind hatine çêkirin. Ji ber rastbûna wan a bilind, dema wan a dirêj, aramiya wan a baş û berxwedana wan a li hember korozyonê, ew her ku diçe di vekolîna hilberan a pîşesaziya nûjen û warên zanistî yên wekî mekanîk a aerofezayê û lêkolînên zanistî de bêtir û bêtir têne bikar anîn.

Awantaj

----Du qat ji hesinê qalibkirî hişktir;

----Guhertinên herî kêm ên pîvanan ji ber guhertinên germahiyê ne;

----Bê pêçandin, ji ber vê yekê kar nayê asteng kirin;

----Ji ber avahiya xwe ya genimê nazik û zeliqîna wê ya hindik, bê çîp û derketin e, ku pileya bilind a rûtbûnê di temenê dirêj ê xizmetê de misoger dike û zirarê nade perçe an amûrên din;

----Xebitandina bê pirsgirêk ji bo karanîna bi materyalên magnetîkî re;

----Jiyanek dirêj û bê zengar, di encamê de lêçûnên lênêrînê kêm in.

Plaqeyên rûyê granîtî yên rastîn bi standardeke bilind a raxbûnê têne pêçandin da ku rastbûn pêk were û wekî bingehek ji bo montajkirina pergalên pîvandina mekanîkî, elektronîkî û optîkî yên sofîstîke têne bikar anîn.

Hin taybetmendiyên bêhempa yên plakaya rûyê granît:

Yekrengiya di Hişkbûnê de;

Rastbûna di bin şert û mercên barkirinê de;

Mijandina Lerizînê;

Paqijkirina hêsan;

Li hember pêçanê berxwedêr;

Porozîteya Kêm;

Ne-Abrasive;

Ne-Mignîtîf

Awantajên Plaqeya Rûyê Granite

First, the rock after a long period of natural aging, uniform structure, coefficient minimum, the internal stress completely disappear, not deformed, so the precision is high.

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Precision Granite Base Can Improve Machine Tool Performances

Requirements are constantly increasing in mechanical engineering in general and in machine tool construction in particular. Achieving maximum precision and performance values without increasing costs are constant challenges to being competitive. The machine tool bed is a decisive factor here. Therefore, more and more machine tool manufacturers are relying on granite. Due to its physical parameters, it offers clear advantages that cannot be achieved with steel or polymer concrete.

Granite is a so-called volcanic deep rock and has a very dense and homogeneous structure with an extremely low coefficient of expansion, low thermal conductivity and high vibration damping.

Below you will discover why the common opinion that granite is mainly only suitable as machine base for high-end coordinate measuring machines is long outdated and why this natural material as a machine tool base is a very advantageous alternative to steel or cast iron even for high-precision machine tools.

We can manufacture granite components for dynamic motion, granite components for linear motors, granite components for ndt, granite components for xray, granite components for cmm, granite components for cnc, granite precision for laser, granite components for aerospace, granite components for precision stages...

High Added Value Without Additional Costs
The increasing use of granite in mechanical engineering is not so much due to the massive increase in the price of steel. Rather, it is because the added value for the machine tool achieved with a machine bed made of granite is possible at very little or no extra cost. This is proven by cost comparisons of well-known machine tool manufacturers in Germany and Europe.

The considerable gain in thermodynamic stability, vibration damping and long-term precision made possible by granite cannot be achieved with a cast iron or steel bed, or only at relatively high cost. For example, thermal errors can account for up to 75% of the total error of a machine, with compensation often attempted for by software – with moderate success. Due to its low thermal conductivity, granite is the better foundation for long-term precision.

With a tolerance of 1 μm, granite easily meets the flatness requirements according to DIN 876 for the degree of accuracy 00. With a value of 6 on the hardness scale 1 to 10, it is extremely hard, and with its specific weight of 2.8g/cm³ it almost reaches the value of aluminium. This also results in additional advantages such as higher feed rates, higher axis accelerations and an extension of the tool life for cutting machine tools. Thus, the change from a cast bed to a granite machine bed moves the machine tool in question into the high-end class in terms of precision and performance – at no extra cost.

Granite’s Improved Ecological Footprint
In contrast to materials such as steel or cast iron, natural stone does not have to be produced with a great deal of energy and using additives. Only relatively small amounts of energy are required for quarrying and surface treatment. This results in a superior ecological footprint, which even at the end of a machine’s life surpasses that of steel as a material. The granite bed can be the basis for a new machine or be used for completely different purposes such as shredding for road construction.

Nor are there any shortages of resources for granite. It is a deep rock formed from magma within the earth’s crust. It has ‘matured’ for millions of years and is available in very large quantities as a natural resource on almost all continents, including all of Europe.

Conclusion: The numerous demonstrable advantages of granite compared to steel or cast iron justify the increasing willingness of mechanical engineers to use this natural material as a foundation for high-precision, high-performance machine tools. Detailed information about granite properties, which are advantageous for machine tools and mechanical engineering, can be found in this further article.

A repeat measurement is a measurement of local flatness areas. The Repeat Measurement specification states that a measurement taken anywhere on the surface of a plate will repeat within the stated tolerance. Controlling local area flatness tighter than overall flatness guarantees a gradual change in surface flatness profile thereby minimizing local errors.

Most manufacturers, including imported brands, adhere to the Federal Specification of overall flatness tolerances but many overlook the repeat measurements. Many of the low value or budget plates available in the market today will not guarantee repeat measurements. A manufacturer who does not guarantee repeat measurements is NOT producing plates that meet the requirements of ASME B89.3.7-2013 or Federal Specification GGG-P-463c, or DIN 876, GB, JJS...

Both are critical to ensure a precision surface for accurate measurements. Flatness specification alone is not sufficient to guarantee measurement accuracy. Take as an example, a 36 X 48 Inspection Grade A surface plate, which meets ONLY the flatness specification of .000300". If the piece being checked bridges several peaks, and the gage being used is in a low spot, the measurement error could be the full tolerance in one area, 000300"! Actually, it can be much higher if the gage is resting on the slope of an incline.

Errors of .000600"-.000800" are possible, depending upon the severity of the slope, and the arm length of the gage being used. If this plate had a Repeat Measurement specification of .000050"F.I.R. then the measurement error would be less than .000050" regardless of where the measurement is taken on the plate. Another problem, which usually arises when an untrained technician attempts to resurface a plate on-site, is the use of Repeat Measurements alone to certify a plate.

The instruments that are used to verify repeatability are NOT designed to check overall flatness. When set to zero on a perfectly curved surface, they will continue to read zero, whether that surface is perfectly flat or perfectly concave or convex 1/2"! They simply verify the uniformity of the surface, not the flatness. Only a plate that meets both the flatness specification AND the repeat measurement specification truly meets the requirements of ASME B89.3.7-2013  or Federal Specification GGG-P-463c.

Ask us about or flatness specification and repeat measurement promise by calling +86 19969991659 or emailing INFO@ZHHIMG.COM

Yes, but they can only be guaranteed for a specific vertical temperature gradient. The effects of thermal expansion on the plate could easily cause a change in accuracy greater than the tolerance if there is a change in the gradient. In some cases, if the tolerance is tight enough, the heat absorbed from overhead lighting can cause enough of a gradient change over several hours.

Granite has a coefficient of thermal expansion of approximately .0000035 inches per inch per 1°F. As an example: A 36" x 48" x 8" surface plate has an accuracy of .000075" (1/2 of Grade AA) at a gradient of 0°F, the top and bottom are the same temperature. If the top of the plate warms up to the point where it is 1°F warmer than the bottom, the accuracy would change to .000275" convex ! Therefore, ordering a plate with a tolerance tighter than Laboratory Grade AA should only be considered if there is adequate climate control.

A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface.

The plate should be supported at these points during production, and it should be supported only at these three points while in use. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same 3 points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. All zhhimg steel stands have support beams designed to line up with the proper support points.

If the plate is properly supported, precise leveling is only necessary if your application calls for it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

Why Choose Granite for Machine Bases and Metrology Components?

The answer is 'yes' for almost every application. The advantages of granite include: No rust or corrosion, almost immune to warping, no compensating hump when nicked, longer wear life, smoother action, greater precision, virtually non-magnetic, low co-efficient of thermal expansion, and low maintenance cost.

Granite is a type of igneous rock quarried for its extreme strength, density, durability, and resistance to corrosion. But granite is also very versatile– it’s not just for squares and rectangles! In fact, Starrett Tru-Stone confidently works with granite components engineered in shapes, angles, and curves of all variations on a regular basis—with excellent outcomes.

Through our state of the art processing, cut surfaces can be exceptionally flat. These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components. Granite is:

machineable
precisely flat when cut and finished
rust resistant
durable
long lasting
Granite components are also easy to clean. When creating custom designs, be sure to choose granite for its superior benefits.

STANDARDS / HIGH WEAR APPLICATIONS
The granite utilized by ZhongHui for our standard surface plate products has high quartz content, which provides greater resistance to wear and damage. Our Superior Black and Crystal Pink colors have low water absorption rates, minimizing the possibility of your precision gages rusting while setting on the plates. The colors of granite offered by ZhongHui result in less glare, which means less eyestrain for individuals using the plates. We have chosen our granite types while considering thermal expansion in an effort to keep this aspect minimal.

CUSTOM APPLICATIONS
When your application calls for a plate with custom shapes, threaded inserts, slots or other machining, you’ll want to select a material like Black Diabase. This natural material offers superior stiffness, excellent vibration dampening, and improved machinability.

Yes, if they are not too badly worn. Our factory setting and equipment allow the optimum conditions for proper plate calibration and rework if necessary. Generally, if a plate is within .001" of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than .001" out of tolerance, or if it is badly pitted or nicked, then it will need to be sent to the factory for grinding prior to relapping.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. We urge you to use caution in selecting your calibration service. Ask for accreditation and verify the equipment that the technician will use has a National Inspection Institution traceable calibration. It takes many years to learn how to properly lap precision granite.

ZhongHui provides quick turn-around on calibrations performed in our factory. Send your plates in for calibration if possible. Your quality and reputation depend on the accuracy of your measurement instruments including surface plates!

Our black surface plates have a significantly higher density and are up to three times as stiff. Therefore, a plate made of the black does not need to be as thick as a granite plate of the same size to have equal or greater resistance to deflection. Reduced thickness means less weight and lower shipping costs.

Beware of others who use lower quality black granite in the same thickness. As stated above, properties of granite, like wood or metal, vary by material and color, and is not an accurate predictor of stiffness, hardness, or wear resistance. In fact, many types of black granite and diabase are very soft and not suitable for surface plate applications.

No. The specialized equipment and training necessary to rework these items requires that they be returned to the factory for calibration and rework.

Yes. Ceramic and granite have similar characteristics, and the methods used to calibrate and lap granite can be used with ceramic items as well. Ceramics are more difficult to lap than granite resulting in a higher cost.

Yes, provided that the inserts are recessed below the surface. If steel inserts are flush with, or above the surface plane, they must be spot-faced down before the plate can be lapped. If required, we can provide that service.

Yes. Steel inserts with the desired thread (English or metric) can be epoxy bonded into the plate at the desired locations. ZhongHui uses CNC machines to provide the tightest insert locations within +/- 0.005”. For less critical inserts, our locational tolerance for threaded inserts is ±.060". Other options include steel T-Bars and dovetail slots machined directly into the granite.

Inserts that are properly bonded using high strength epoxy and good workmanship will withstand a great deal of torsional and shear force. In a recent test, using 3/8"-16 threaded inserts, an independent testing laboratory measured the force required to pull an epoxy-bonded insert from a surface plate. Ten plates were tested. Out of these ten, in nine cases, the granite fractured first. The average load at the point of failure was 10,020 lbs. for gray granite and 12,310 lbs. for black. In the single case where an insert pulled free of the plate, the load at the point of failure was 12,990 lbs.! If a work piece forms a bridge across the insert and extreme torque is applied, it is possible to generate enough force to fracture the granite. Partially for this reason, ZhongHui gives guidelines for the maximum safe torque that can be applied the epoxy bonded inserts: https://www.zhhimg.com/standard-thread-inserts-product/

Yes, but only at our factory. At our plant, we can restore almost any plate to 'like-new' condition, usually for less than half the cost of replacing it. Damaged edges can be cosmetically patched, deep grooves, nicks, and pits can be ground out, and the attached supports can be replaced. In addition, we can modify your plate to increase its versatility by adding solid or threaded steel inserts and cutting slots or clamping lips, per your specifications.

Why Choose Granite?
Granite is a type of igneous rock formed in the Earth millions of years ago. The composition of igneous rock contained many minerals such as quartz that is extremely hard and wear-resistant. In addition to hardness and wear resistance granite has approximately half the coefficient of expansion as cast iron. As its volumetric weight is approximately one third that of cast iron, granite is easier to manoeuvre.

For machine bases and metrology components, black granite is the colour most used. Black granite has a higher percentage of quartz than other colours and is, therefore, the hardest wearing.

Granite is cost-effective, and cut surfaces can be exceptionally flat. Not only can it be hand lapped to achieve extremes of accuracy, but re-conditioning can be performed without moving the plate or table off-site. It is entirely a hand lapping operation and generally costs much less than re-conditioning a cast iron alternative.

These qualities make granite the ideal material to create custom-size and custom-design machine bases and metrology components such as the granite surface plate.

ZhongHui produces bespoke granite products that are created to support specific measurement requirements. These bespoke items vary from straight edges to tri squares. Due to the versatile nature of granite, the components can be produced to any size required; they are hard wearing and long-lasting.

Advantages of Granite Surface Plates
The importance of measuring on an even surface was established by British inventor Henry Maudsley in the 1800s. As a machine tool innovator, he determined that consistent production of parts required a solid surface for reliable measurements.

The industrial revolution created a demand for measuring surfaces, so engineering company Crown Windley created manufacturing standards. The standards for surface plates were first set by Crown in 1904 using metal. As the demand and cost for metal increased, alternative materials for the measuring surface were investigated.

In America, monument creator Wallace Herman established that black granite was an excellent surface plate material alternative to metal. As granite is non-magnetic and doesn’t rust, it soon became the preferred measuring surface.

A granite surface plate is an essential investment for laboratories and test facilities. A granite surface plate of 600 x 600 mm can be mounted on a support stand. The stands provide a working height of 34” (0.86m) with five adjustable points for levelling.

For reliable and consistent measurement results, a granite surface plate is crucial. As the surface is a smooth and stable plane, it enables instruments to be carefully manipulated.

The main advantages of granite surface plates are:

• Non-reflective
• Resistant to chemicals and corrosion
• Low coefficient of expansion compared with cart iron so less affected by temperature change
• Naturally rigid and hard-wearing
• The plane of the surface is unaffected if scratched
• Will not rust
• Non-magnetic
• Easy to clean and maintain
• Calibration and resurfacing can be done onsite
• Suitable for drilling for threaded support inserts
• High vibration damping

For many shops, inspection rooms and laboratories, precision granite surface plates are relied on as the basis for accurate measurement. Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining. They also are ideal bases for making height measurements and gaging surfaces. Further, a high degree of flatness, stability, overall quality and workmanship make them a good choice for mounting sophisticated mechanical, electronic and optical gaging systems. For any of these measurement processes, it is imperative to keep surface plates calibrated.

Repeat Measurements and Flatness
Both flatness and repeat measurements are critical to ensure a precision surface. Flatness can be considered as all points on the surface being contained within two parallel planes, the base plane and the roof plane. The measurement of distance between the planes is the overall flatness of the surface. This flatness measurement commonly carries a tolerance and may include a grade designation.

The flatness tolerances for three standard grades are defined in the federal specification as determined by the following formula:
Laboratory Grade AA = (40 + diagonal² / 25) x 0.000001 inch (unilateral)
Inspection Grade A = Laboratory Grade AA x 2
Tool Room Grade B = Laboratory Grade AA x 4

In addition to flatness, repeatability must be ensured. A repeat measurement is a measurement of local flatness areas. It is a measurement taken anywhere on the surface of a plate that will repeat within the stated tolerance. Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.

To ensure a surface plate meets both the flatness and repeat measurement specifications, manufacturers of granite surface plates should use Federal Specification GGG-P-463c as a basis for their specifications. This standard addresses repeat measurement accuracy, material properties of surface plate granites, surface finish, support point location, stiffness, acceptable methods of inspection and installation of threaded inserts.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

Checking Plate Accuracy
By following a few simple guidelines, an investment in a granite surface plate should last for many years. Depending on plate usage, shop environment and required accuracy, frequency of checking the surface plate accuracy varies. A general rule of thumb is for a new plate to receive a full recalibration within one year of purchase. If the plate is used frequently, it is advisable to shorten this interval to six months.

Before a surface plate has worn beyond specification for overall flatness, it will show worn or wavy posts. Monthly inspection for repeat measurement errors using a repeat reading gage will identify wear spots. A repeat reading gage is a high-precision instrument that detects local error and can be displayed on a high magnification electronic amplifier.

An effective inspection program should include regular checks with an autocollimator, providing actual calibration of overall flatness traceable to National Institute of Standards and Technology (NIST). Comprehensive calibration by the manufacturer or an independent company is necessary from time to time.

Variations Between Calibrations
In some cases, there are variations between surface plate calibrations. Sometimes factors such as surface change resulting from wear, incorrect use of inspection equipment or use of noncalibrated equipment can account for these variations. The two most common factors, however, are temperature and support.

One of the most important variables is temperature. For instance, the surface might have been washed with a hot or cold solution prior to calibration and not allowed sufficient time to normalize. Other causes of temperature change include drafts of cold or hot air, direct sunlight, overhead lighting or other sources of radiant heat on the surface of the plate.

There also can be variations in the vertical temperature gradient between winter and summer. In some cases, the plate is not allowed sufficient time to normalize after shipment. It is a good idea to record the vertical gradient temperature at the time the calibration is performed.

Another common cause for calibration variation is a plate that is improperly supported. A surface plate should be supported at three points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered.

Only three points can rest solidly on anything but a precision surface. Attempting to support the plate at more than three points will cause the plate to receive its support from various combinations of three points, which will not be the same three points on which it was supported during production. This will introduce errors as the plate deflects to conform to the new support arrangement. Consider using steel stands with support beams designed to line up with the proper support points. Stands for this purpose are generally available from the surface plate manufacturer.

If the plate is properly supported, precise leveling is only necessary if an application specifies it. Leveling is not necessary to maintain the accuracy of a properly supported plate.

It is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages. Cover plates to protect them from dust and damage. Wear life can be extended by covering the plate when not in use.

Extend Plate Life
Following a few guidelines will reduce wear on a granite surface plate and ultimately, extend its life.

First, it is important to keep the plate clean. Airborne abrasive dust is usually the greatest source of wear and tear on a plate, as it tends to embed in workpieces and the contact surfaces of gages.

It also is important to cover plates to protect it from dust and damage. Wear life can be extended by covering the plate when not in use.

Rotate the plate periodically so that a single area does not receive excessive use. Also, it is recommended to replace steel contact pads on gaging with carbide pads.

Avoid setting food or soft drinks on the plate. Many soft drinks contain either carbonic or phosphoric acid, which can dissolve the softer minerals and leave small pits in the surface.

Where to Relap
When a granite surface plate needs re-surfacing, consider whether to have this service performed on-site or at the calibration facility. It is always preferable to have the plate relapped at the factory or a dedicated facility. If, however, the plate is not too badly worn, generally within 0.001 inch of the required tolerance, it can be resurfaced on-site. If a plate is worn to the point where it is more than 0.001 inch out of tolerance, or if it is badly pitted or nicked, then it should be sent to the factory for grinding prior to relapping.

A calibration facility has the equipment and factory setting providing the optimum conditions for proper plate calibration and rework if necessary.

Great care should be exercised in selecting an on-site calibration and resurfacing technician. Ask for accreditation and verify the equipment that the technician will use has a NIST-traceable calibration. Experience also is an important factor, as it takes many years to learn how to correctly lap precision granite.

Critical measurements start with a precision granite surface plate as a baseline. By ensuring a reliable reference by using a properly calibrated surface plate, manufacturers have one of the essential tools for reliable measurements and better quality parts.

Checklist for Calibration Variations

1. The surface was washed with a hot or cold solution prior to calibration and was not allowed sufficient time to normalize.
2. The plate is improperly supported.
3. Temperature change.
4. Drafts.
5. Direct sunlight or other radiant heat on the surface of the plate. Be sure that overhead lighting is not heating the surface.
6. Variations in the vertical temperature gradient between winter and summer. If at all possible, know the vertical gradient temperature at the time the calibration is performed.
7. Plate not allowed sufficient time to normalize after shipment.
8. Improper use of inspection equipment or use of noncalibrated equipment.
9. Surface change resulting from wear.

Tech Tips
Because every linear measurement depends on an accurate reference surface from which final dimensions are taken, surface plates provide the best reference plane for work inspection and layout prior to machining.

Controlling local area flatness to a tighter tolerance than overall flatness guarantees a gradual change in surface flatness profile, thereby minimizing local errors.