316L Implantable Enclosure
316L Implantable Enclosure
Small sealed 316L stainless steel capsule for a sterile electronic implant.
| Material | 316L stainless steel |
|---|---|
| Draw depth | 24 mm |
| Wall thickness | 0.4 mm |
| Tolerance | ±0.05 mm |
| Forming route | Single draw + light ironing |
| Measured LDR | 1.85–2.05 |
The challenge
An implantable enclosure has to be biocompatible, sealed and clean. The drawn surface must be free of tool marks that could trap contamination, the inside must have no burr that could shed particles, and the wall has to be uniform enough for a reliable laser weld to the lid.
Because the part is small, a 0.4 mm wall leaves little room for variation — a few hundredths of a millimetre changes the weld gap and the fit of the feed-through. We hold the wall with a light ironing pass rather than relying on the draw, and we keep the interior as a continuous drawn surface so there is no cut edge to shed particles.
Downstream, the capsule is laser-welded to a lid and often carries a feed-through, so the wall at the weld and at the feed-through has to be uniform. A local thin spot there is where a seal fails.
How AUNOV draws it
316L is specified for its corrosion resistance and biocompatibility; the draw is kept to one stage so the grain flow stays even and the surface stays clean, which matters more than speed for an implantable part.
- 316L selected for corrosion resistance and biocompatibility
- Single draw plus light ironing to set a smooth wall at 0.4 mm
- Deburr and clean the interior for particle-free handling
- Dimensional and surface check before clean-room-compatible packing
Process control and inspection
Interior cleanliness is checked by a particle count after deburr and clean, since the enclosure has to be particle-free before it leaves our hands; a single burr would defeat the sealed design.
The wall is measured at several points rather than one, because at 0.4 mm a small variation changes the laser-weld gap to the lid and the fit of any feed-through.
What this means for your part
If your enclosure is a small 316L stainless steel capsule for a medical device, this draw-and-iron route is a proven starting point. Confirm the weld interface and surface-finish requirement and we adjust the route.
We pack the enclosures in a clean-room-compatible state and keep the lot data on file, so a first-article review can trace the coil, the tool and the wall measurement for each batch.
- Confirm the weld interface and surface finish; the draw-and-iron route is tuned to both.
- If a feed-through passes through the wall, give its position so we hold the wall there.
- Plan for clean-room-compatible packing; we supply the enclosure in that state and keep lot data for first-article review.
Frequently asked questions
Can 316L stainless steel be deep drawn for a medical implant?
Direct answer: Yes. 316L is commonly deep drawn for implantable and surgical enclosures because of its corrosion resistance and biocompatibility. AUNOV draws it with a light ironing pass to get a smooth wall and a clean interior.
How do you avoid burrs inside a drawn medical enclosure?
Direct answer: The draw itself leaves no cut edge inside; burrs only appear where the part is trimmed or pierced. AUNOV deburrs and cleans the interior after drawing so the enclosure is particle-free before packing.
What wall tolerance can an implantable 316L capsule hold?
Direct answer: AUNOV holds ±0.05 mm on the drawn capsule wall, with a light ironing pass used to set the wall rather than the draw alone. Because the part is small, we check the wall at several points so the laser-weld gap to the lid stays consistent.
Have a similar part?
Send the drawing and material — AUNOV returns a DFM review and a quote within 24 hours.
Request a quoteSources Behind These Examples
Each example is built on measured material data and the process taxonomy set out by these standards. We keep the lot data behind each part on file for first-article review.
- ASTM E646 — Standard Test Method for Tensile Strain-Hardening Exponents (n) of Metallic Sheet Materials. The n-value sets how much a wall can thin before necking.
- DIN 8584 — Manufacturing processes, forming: classification of deep drawing operations and their subgroups.
- ISO 20482 — Metallic materials: Erichsen cupping test, a formability measure complementary to LDR.
- Wikipedia: Anisotropy — explains the r-value and why earing directions form.
- Wikipedia: Work hardening — why redraws and intermediate annealing matter.