Design Guide - Technical Ceramics
The following design tips are intended to aid to engineers and designers to produce cost effective designs for advanced ceramic manufacture. These are general rules of thumb, and as always, rules can be broken if necessary.
1. Compression Is Key
Design for part for compressive stresses. Where possible avoid tensile and bending stresses. Almost all advanced ceramics have very high compressive stress capabilities, but only a few have high tensile stress capabilities.
2. Cut the Corners
Where possible, reduce the section thickness of the component. Try to relieve sharp corners by chamfers or radii. Perfectly sharp corners are difficult due to the almost inevitable radius that is generated during the manufacturing process.
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3. Keep it Uniform
Keeping the wall thickness of the part uniform will result in a better, stronger part. Non-uniform wall thicknesses cause internal stresses in the part that could cause premature failure, or difficulties during the firing process.
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4. Tolerate Being Dimensional
The parts produced are supplied to the customer "as sintered", meaning that no post processing of the part (i.e. grinding) will be performed. A general rule of thumb is +/- 2% tolerance for ANY dimension in the design. If a tighter dimension is required, please contact us regarding your specific application and requirements. Tighter tolerances will increase the cost of the part.
5. Too Close to the Edge
Placing holes too close to the edge may cause burn through when the part is fired. There is also a chance of failure when the part is placed into service because of the thin cross-section that would exist between the hole and the outside edge. Try to keep holes greater than 3mm away from the edge.
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6. Make Big Holes
If using a through-hole for bolting the part to an assembly, make the hole as large as possible. This allows the tolerance requirements to be relaxed for hole-to-hole location and ensures your part will fit. If a larger hole is not possible, please consider using slots (see below).
7. Slots Are Us
If larger holes cannot be used because of certain design criteria, consider using a slotted hole. Slotting allows the hole-to-hole dimensional tolerances to be relaxed, which ensures your part will fit the assembly properly.
8. Being Shallow is Good
If blind holes are to be used, try to keep the hole as shallow as possible. This eases the manufacture of the part and will reduce part cost.
9. Beware of Threads
Generally, threads should be avoided if at all possible.
If threads must be used, consider the largest pitch (most coarse) thread possible. Fine threads generally do not survive the firing process due to their being thin. The use of threads will generally increase the cost of the part. If part will be removed and replaced often, consider using a metal thread insert.
If threads must be used, consider the largest pitch (most coarse) thread possible. Fine threads generally do not survive the firing process due to their being thin. The use of threads will generally increase the cost of the part. If part will be removed and replaced often, consider using a metal thread insert.
