Ordering custom technical ceramics is not like ordering CNC metal parts. The manufacturing process—involving powder compaction, green body machining, and high-temperature sintering—introduces unique challenges regarding shrinkage and precision.
At Yixing Yanyun, we process hundreds of custom drawings every month for aerospace, semiconductor, and industrial clients.
In this guide, our engineering team answers the top 5 questions we receive about customizing Alumina, Zirconia, and Yttria components, helping you design better parts and get accurate quotes faster.
1. What tolerances can you achieve?
This is the most common question. The answer depends on whether you need “As-Fired” parts or “Precision Machined” parts.
A. Standard “As-Fired” Tolerances (Most Cost-Effective)
When ceramic is sintered, it shrinks by approximately 15-20%. While we calculate this precisely, some variation is natural.
- Standard Tolerance: ±0.2mm to ±0.3mm (or roughly ±1% – 1.5% of dimensions).
- Best For: Crucibles, saggars, and structural parts where “perfect” fit is not critical.
B. Precision Machined Tolerances (High Performance)
If your part requires tight assembly fits (e.g., a piston, a vacuum seal, or a semiconductor chuck), we perform secondary diamond grinding after sintering.
- Precision Tolerance: We can achieve ±0.02mm.
- Surface Finish: We can polish surfaces to Ra > 0.2.
- Note: Precision machining adds to the cost. We recommend marking critical dimensions on your drawing so we only machine what is necessary.
2. What is the minimum wall thickness?
Designing ceramic parts too thin is the #1 cause of warping during sintering.
- Small Parts (< 10mm diameter): We can achieve a wall thickness down to 1mm.
- Medium/Large Parts (approx. 100mm diameter): We strongly recommend a minimum wall thickness of 5mm – 6mm.
Engineering Tip: For custom crucibles or tubes, a thicker wall not only prevents deformation during production but also significantly extends the service life by resisting thermal shock better.
3. Do I need to pay for a mold?
If your part requires a specific shape (like a crucible with a unique taper) that we don’t have in stock, we need to create a custom mold for isostatic pressing or slip casting.
- Mold Cost: It is surprisingly affordable. For a typical “cup-sized” component, mold costs often range from $200 to $300 USD.
- Refund Policy: We support our partners. If your cumulative order volume reaches a certain quantity (typically 100+ pieces, depending on complexity), we refund the mold cost 100%.
Exception: For flat parts like Alumina Ceramic Plates, we often don’t need a mold. We can precision-cut them from larger stock blanks, saving you money.
4. How long does it take? (Lead Times)
Time is money. We offer two speed tiers based on the manufacturing method:
Tier 1: Fast Track (3–4 Days)
- Applicable for: Custom-cut ceramic plates, substrates, and simple machining from stock bars.
- Why so fast? We keep large master blanks of 99% and 99.5% Alumina in stock. We simply program our laser or diamond cutter, and your order is ready to ship.
Tier 2: Custom Molding (2–3 Weeks)
- Applicable for: Custom crucibles, tubes, and complex 3D shapes.
- The Process: Design Mold (3 days) → Make Mold & Form Body (5 days) → Drying (Critical step, 3-5 days) → Sintering (2 days) → Inspection.
- Note: You cannot rush the drying process. Drying too fast causes internal cracks that only show up later in your furnace.
5. Can you make complex features like threads or holes?
Yes.
- Holes: We can create through-holes or blind holes. For high precision, we drill these after sintering. The minimum diameter is generally 0.5mm.
- Threads (Internal/External): We can machine threads, but please note that ceramic threads are brittle. We often recommend a design change to use metal inserts or clamping mechanisms if the thread will be under high mechanical stress.
Ready to start?
Don’t let the complexity of ceramics slow down your project. Send us your CAD file (PDF, DWG, or STP), and our engineers will review it for manufacturability.
