Domestic general-purpose CMM granite base (Jinan Qinghui Changyan, Grade 00\/000), compared with a control group of HT250 cast iron base of the same size;
Core physical property benchmarks (National Standards GB\/T 22095, JJG117):
Jinan Qing linear expansion coefficient \u03b1: 4.5~6\u00d710\u207b\u2076\/\u2103
Cast iron HT250 \u03b1: 11.5~13\u00d710\u207b\u2076\/\u2103
Granite internal damping ratio: 0.015~0.020 (Cast iron only 0.004~0.006)
Shore hardness HS72; Density 2.68g\/cm\u00b3, non-magnetic, rust-proof<\/li>\n\n\n\n
Sensor array: Distributed temperature sensors, laser displacement meters, strain gauges, vibration accelerometers;
Test points: Grid layout on the base working surface (edges center dense points on guide rail mounting surfaces);
Environmental conditions categorized into two types:
Condition A: Standard constant temperature metrology room 20\u00b11\u2103, humidity 50%\u00b15%;
Condition B: Ordinary machining workshop, diurnal temperature difference \u00b13~5\u2103, interference from air compressors and overhead cranes;
Monitoring cycle: Short-term continuous 48h thermal deformation monitoring, medium-to-long-term 12-month accuracy drift tracking.<\/li>\n\n\n\n
Temperature field uniformity, linear thermal deformation, gradient temperature field bending deformation, vibration attenuation characteristics, long-term flatness creep drift, load deformation recoverability.<\/li>\n<\/ol>\n\n\n\n
II. Comparative Analysis of Temperature Deformation Monitoring Data (Core Error Sources)<\/p>\n\n\n\n
- \n
- Homogeneous Constant Temperature Environment (20\u00b11\u2103, 48h continuous operation)
Base specifications 1200\u00d71000\u00d7150mm, continuous online CMM testing, heat source from continuous heating of three-axis servo motors.<\/li>\n<\/ol>\n\n\n\nMat\u00e9riau<\/th> Maximum surface temperature difference<\/th> Total expansion per meter \u0394L<\/th> 48h measurement repeatability drift<\/th><\/tr><\/thead> Jinan Qing Granite<\/td> \u22641.8\u2103<\/td> \u22640.006mm\/m<\/td> 0.6~0.8\u03bcm<\/td><\/tr> HT250 Cast Iron<\/td> 7.5~8.2\u2103<\/td> 0.014mm\/m<\/td> 2.1~2.5\u03bcm<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n Data Conclusions:
Granite has slow thermal conductivity, heat diffuses uniformly, and has no local high-temperature zones; cast iron easily forms a temperature gradient with a hot center and cold edges, producing arching deformation;
Under the same temperature rise, the thermal deformation of granite is only 1\/2 of cast iron, reducing system measurement drift by more than 65%;
Gradient temperature difference is the main cause of form and position errors; cast iron bases easily cause three-axis perpendicularity and flatness datum shifts, while granite can significantly reduce the pressure on compensation algorithms.<\/p>\n\n\n\n- \n
- Workshop Variable Temperature Conditions (5\u2103 diurnal temperature difference cycle for 72h)
Cycle range 17\u2103~22\u2103, simulating a summer workshop scenario without strict temperature control:
Granite base dimensional lag deformation: Reaches stability 2~3h after temperature change, residual permanent deformation \u22640.4\u03bcm\/m;
Cast iron base deformation lag exceeds 6h, each temperature cycle produces irreversible micro-creep, with a cumulative drift of 12~18\u03bcm\/m per year;
After 72h of cold-hot cycling, the dimensional recovery rate of granite is 99.98%, while cast iron is only 96.2%, with the long-term usage datum continuously sinking and warping.<\/li>\n\n\n\n - Thermal Deformation Mathematical Model (Granite Base)
Uniform temperature field linear deformation formula:
(\\Delta L = L_0 \\times \\alpha \\times \\Delta T)
Gradient temperature field bending deformation: Granite has a large cross-sectional moment of inertia, and its bending deflection is only 1\/3 of cast iron, significantly suppressing the datum tilt error of the CMM Y and Z axes.<\/li>\n<\/ol>\n\n\n\nIII. Vibration Damping Monitoring Data Analysis
Simulated workshop multi-frequency vibrations (air compressor 50Hz, ground low-frequency resonance 2~10Hz, personnel walking impact), laser displacement sensor collects table amplitude and decay time:
Granite vibration decay time after excitation <0.5s; cast iron decay \u22652.6s;
Under equivalent external excitation, granite steady-state amplitude <1.8\u03bcm, cast iron amplitude 6~9\u03bcm;
At the moment of CMM probe contact with the workpiece: cast iron bases easily exhibit data jumps of 3~6\u03bcm, granite shows no jumps, measurement repeatability consistency improves by 70%;
High damping characteristics reduce air bearing resonance wear of the equipment, extending the service life of CMM gratings and guide rails.
IV. Long-term Stability 12-Month Accuracy Drift Monitoring Data
Samples: Grade 00 Jinan Green CMM base, same-specification cast iron base, daily 8h use in a standard constant temperature workshop:
Granite base flatness annual drift: \u22640.5\u03bcm\/m, no obvious creep curve;
Cast iron base flatness annual drift: 8~12\u03bcm\/m, requires regrinding and calibration after 3 years;
Stress mechanism: Granite undergoes natural geological aging over millions of years, with no internal stress release after 6~12 months of artificial stress relief before factory release; cast iron casting stress is slowly released year by year, causing continuous warping;
O&M data: Granite bases are re-inspected on average every 5~8 years, cast iron is calibrated annually, with a difference in regrinding and renovation costs of over 200%;
V. Load Deformation and Recovery Monitoring Data
Uniform load 0~4t stepwise loading, full load static for 24h, unloading and observing rebound:
Granite maximum elastic deformation 1.2\u03bcm\/t, 100% complete rebound after unloading, no plastic deformation;
Cast iron elastic deformation 3.1\u03bcm\/t, minor plastic sinking exists under long-term heavy loads;
Domestic aerospace and new energy CMM workpieces are generally <500kg, granite has sufficient load-bearing margin, and heavy-load benchmarks suffer no permanent damage.
VI. Environmental Interference Additional Monitoring (Corrosion, Magnetization, Wear)
Long-term spraying of cutting fluid and emulsion for 180 days: granite shows no corrosion or rust spots; cast iron produces oxidation bumps, destroying flatness;
Long-term placement of magnetic steel parts: granite does not adsorb iron filings; cast iron magnetizes, and debris accumulation causes measurement false highs;
500,000-cycle workpiece push-pull wear test: granite working surface wear <0.3\u03bcm, cast iron scratch depth 3~8\u03bcm.
VII. Comprehensive Data Conclusions and Engineering Application Guidance<\/p>\n\n\n\n- \n
- Quantifying Core Advantages (Data Support)
Thermal stability: Under the same temperature difference, thermal deformation is only 50% of cast iron, and bending error in gradient temperature fields is reduced by 67%;
Vibration suppression: Vibration decay speed is improved by 5 times, and measurement repeatability error is reduced by 60% ;
Long-term accuracy: Annual benchmark drift <0.5\u03bcm\/m, cast iron base drift exceeds 10\u03bcm\/m;
O&M costs: Comprehensive costs of calibration, regrinding, and rust prevention maintenance decrease by over 60%.<\/li>\n\n\n\n - Domestic Selection Grading Data Standards (GB\/T22095)
Tableau
Accuracy Grade Flatness Tolerance \u03bcm\/m Suitable CMM Scenarios Recommended Granite Raw Material
Grade 000 \u22641.0 Metrology institutes, semiconductor nano-detection Super Grade Jinan Green
Grade 00 \u22642.0 Aerospace, precision mold CMM Standard Jinan Green \/ Indian Black
Grade 0 \u22644.0 General machinery component inspection Zhangqiu Green, Fujian Granite<\/li>\n\n\n\n - Monitoring Data Implementation and Optimization Plan
Intelligent Compensation: Embed a temperature sensor array in the granite base, establish a machine learning error model based on monitored thermal deformation data, and actively compensate via OPC UA integration with the CMM control system;
Working Condition Adaptation: Constant-temperature workshops must use granite bases to offset micron-level system errors caused by diurnal temperature fluctuations;
Preventive Maintenance: Export monitoring data annually for regression analysis to predict flatness drift and plan re-inspections in advance;
Export Selection: For export to variable-temperature workshops in India and Southeast Asia, prioritize providing Jinan Qing 00-grade bases paired with CMMs to reduce accuracy complaints at customer sites.<\/li>\n<\/ol>\n\n\n\n![\"\"](\"https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/08\/7-1024x724.png\")
<\/figure>","protected":false},"excerpt":{"rendered":"Data Monitoring and Analysis Report on Granite Bases for Chinese CMMs I. Monitoring Objects and Basic Conditions II. Comparative Analysis of Temperature Deformation Monitoring Data (Core Error Sources) Material Maximum surface temperature difference Total expansion per meter \u0394L 48h measurement repeatability drift Jinan Qing Granite \u22641.8\u2103 \u22640.006mm\/m 0.6~0.8\u03bcm HT250 Cast Iron 7.5~8.2\u2103 0.014mm\/m 2.1~2.5\u03bcm Data…<\/p>","protected":false},"author":1,"featured_media":3238,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kadence_starter_templates_imported_post":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":""},"categories":[35],"tags":[],"class_list":["post-3237","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"taxonomy_info":{"category":[{"value":35,"label":"NEWS"}]},"featured_image_src_large":["https:\/\/jtlcnc.com\/wp-content\/uploads\/2026\/08\/7-1024x724.png",1024,724,true],"author_info":{"display_name":"jinxing6611@gmail.com","author_link":"https:\/\/jtlcnc.com\/fr\/author\/jtlcnc\/"},"comment_info":0,"category_info":[{"term_id":35,"name":"NEWS","slug":"news","term_group":0,"term_taxonomy_id":35,"taxonomy":"category","description":"","parent":0,"count":361,"filter":"raw","cat_ID":35,"category_count":361,"category_description":"","cat_name":"NEWS","category_nicename":"news","category_parent":0}],"tag_info":false,"_links":{"self":[{"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/posts\/3237","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/comments?post=3237"}],"version-history":[{"count":1,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/posts\/3237\/revisions"}],"predecessor-version":[{"id":3239,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/posts\/3237\/revisions\/3239"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/media\/3238"}],"wp:attachment":[{"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/media?parent=3237"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/categories?post=3237"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jtlcnc.com\/fr\/wp-json\/wp\/v2\/tags?post=3237"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
- Quantifying Core Advantages (Data Support)
- Workshop Variable Temperature Conditions (5\u2103 diurnal temperature difference cycle for 72h)