Precision fine-grain graphite molds for 3D glass hot bending, built around glass datasheet review, furnace atmosphere control, polished cavity surfaces, and dimensional repeatability.
Source-reviewed on July 23, 2026. These boundaries support RFQ screening only; the released mold quote still depends on the customer glass datasheet, drawing, and furnace log.
Evidence: The checker uses 600-850°C as a preliminary review window because public cover-glass data puts the strain, annealing, and softening context in that region.
Action: Quote release still needs the exact glass datasheet, peak hold time, cooling profile, and furnace atmosphere log.
Evidence: Public cover-glass CTE and isostatic graphite CTE examples do not match one-for-one, so cavity geometry cannot be copied directly from the cold target shape.
Action: Confirm the glass CTE, mold grade CTE, contact side, forming pressure, and cooling support before final offset machining.
Evidence: Fine isostatic grades are favored because grain size and density influence polish response, particle release, and glass-contact surface stability.
Action: Specify Ra target, allowed pits/haze, polishing sequence, cleaning method, and inspection datum in the RFQ.
Evidence: Ion exchange creates the compressive surface layer; high-temperature forming should not be assumed compatible with already strengthened glass.
Action: Treat hot bending before final strengthening as the default unless the customer process owner signs off on another validated sequence.
The tool screens whether the request is ready for automatic RFQ review. The report below explains which evidence still controls production release.
Public references checked on July 23, 2026. They support the page logic but do not replace customer drawings, internal process recipes, or production qualification.
| Decision Point | Public Source | How It Is Used | Limit |
|---|---|---|---|
| Cover-glass thermal context | Corning Gorilla Glass 6 product information sheet | Public reference values include 572°C strain point, 624°C annealing point, 885°C softening point, and 75.2 x 10^-7/°C CTE. | Use only as a public cover-glass reference. The customer glass datasheet controls the mold quote. |
| Isostatic graphite grade window | SGL Carbon SIGRAFINE ISO graphite technical data sheet | Published isostatic graphite examples list 3-20 µm grain size, 1.72-1.88 g/cm³ density, and 2.7-4.7 x 10^-6/K CTE by grade. | Supplier grade, block size, purification, and machining direction still need drawing-level confirmation. |
| Oxygen exposure risk | Idaho National Laboratory graphite oxidation comparison | Oxidation behavior changes materially across nominal 550-800°C test temperatures and depends on oxygen transport to the graphite surface. | Nuclear graphite tests are not mold-life guarantees; they support oxygen-control risk screening only. |
| Strengthening sequence boundary | Corning science note on ion-exchange strengthening | Corning explains chemical strengthening as ion exchange that forms a surface compressive layer. | Final bend/strengthen order must be approved by the glass process owner and part qualification plan. |
Send the drawing, glass datasheet, peak temperature, atmosphere trend, and target surface finish together so the mold quote can be checked against the same boundaries used on this page.
Complete RFQs are easier to review within 1-2 business days when drawings, graphite grade, quantity, and destination are included.
| Material Option | Best Fit Application | Watchouts & Risks |
|---|---|---|
| Isostatic Ultra-Fine Grain Graphite | Smartphone 3D glass and high-end wearables requiring flawless surface finish. | Higher initial cost, but lower cost-per-part due to longer mold life. |
| Standard Fine Grain Graphite | Automotive displays and larger 3D glass with less aggressive curvature. | May require more frequent repolishing in high-volume production. |
| Anti-Oxidation Treated Graphite | Hot bending processes in environments with higher oxygen exposure. | Treatment type must be compatible with the specific glass composition to avoid sticking. |
Evaluate the 3D model against the glass bending temperature, cycle time, and cooling profile.
Select the optimal graphite grade to balance surface finish, oxidation resistance, and cost.
Machine the cavity with specialized tooling, followed by polishing to meet strict Ra targets.
Verify 3D contour accuracy with CMM and pack securely to prevent edge chipping during transit.
| Metric | Typical Range | Why It Matters |
|---|---|---|
| Surface Finish (Ra) | 0.4 - 0.8 µm (or better with special polishing) | Directly impacts the optical clarity of the formed 3D glass. |
| Thermal Expansion Coefficient (CTE) | 4.0 - 5.5 x 10^-6 /°C | Must be compatible with the glass to prevent sticking or cracking during cooling. |
| Expected Mold Life | 500 - 1500+ cycles after atmosphere and polish review | Determines the tooling cost for mass production runs, but only after temperature, O2 exposure, and cleaning are known. |
| Furnace Oxygen Control | N2 or inert process with O2 ppm trend supplied | Graphite mold life and glass-contact surface stability depend on oxygen ingress near the hot zone. |
Isostatic ultra-fine grain graphite is the usual starting point because dense, fine grades polish more predictably and hold glass-contact surfaces better. The final grade still depends on glass CTE, peak temperature, O2 exposure, cavity geometry, and the required Ra.
For initial costing, buyers often discuss 500-1500 cycles before repolishing or replacement. Treat that as a planning range only; oxygen ingress, hold time, cleaning, release chemistry, and surface finish decide the real maintenance interval.
Yes. We utilize high-speed CNC machining centers and CMM inspection to ensure the 3D contours meet strict smartphone OEM tolerances.
Send the STEP or IGES model, 2D tolerances, glass datasheet, target Ra, peak temperature, hold time, cooling profile, atmosphere/O2 log, required cycle life, and expected monthly volume.
Only after engineering review. Different glass CTE, softening behavior, thickness, coating, and strengthening sequence can change cavity compensation and sticking risk.
The default assumption is hot bending before final ion-exchange strengthening. If the customer wants to bend already strengthened glass, the process owner should provide qualification evidence before the mold is released.
It is considered when peak temperature, hold time, or oxygen exposure increases oxidation risk. Treatment choice must be checked against glass-contact cleanliness and sticking behavior.
Inquiry Email
Complete RFQs are easier to review within 1-2 business days when drawings, grade, quantity, and destination are included.
WhatsApp Alignment
+8618857971991
Use WhatsApp for quick alignment; send drawings by email for traceable review.
