Deep Drawn vs Machined vs Welded Housings
Deep Drawn vs. Machined vs. Welded: Choosing the Right Process for Your Sensor Housing
Ask three suppliers how to make a sensor housing and you will get three different processes back — each quoting the method their machines happen to run. Here is an honest comparison from a factory that runs deep drawing every day (and sends work out when another process genuinely fits better).
The three routes, in one paragraph each
Deep drawing forms a flat blank into a seamless shell with a press and die. One stroke, no joints, and the metal’s grain flow follows the part’s shape. Unit cost drops sharply at volume; the trade-off is tooling cost up front.
CNC machining carves the housing from solid bar or block. It offers total geometric freedom and zero tooling investment, but every gram of removed metal is paid for in machine time — and the price per piece barely improves as volumes grow.
Welded construction rolls sheet into a tube and welds the seam, or welds a machined base to a drawn body. It handles large diameters and hybrid geometries well, but introduces a seam: a heat-distorted zone, a potential leak path, and a quality variable that lives in your welder’s hands.
Head-to-head
| Factor | Deep drawn | CNC machined | Welded shell |
|---|---|---|---|
| Piece cost at volume | Lowest | Highest | Medium |
| Tooling investment | Required | None | Low–medium |
| Leak path risk | None (seamless) | None (from solid) | The seam itself |
| Wall consistency | Excellent | Varies with program | Seam zone differs |
| Deep/thin geometry | Excellent | Time-prohibitive | Limited |
| Lead time to samples | Weeks (tooling) | Days | Days |
| Best volume range | 10k–10M+/yr | Prototypes–10k/yr | Medium–high |
Where deep drawing clearly wins
Closed-end shells. A closed end formed by the die — not welded on, not machined from solid — is the cheapest and strongest way to seal one side of a housing. Every deep drawn part gets this for free.
Work hardening. The draw itself strengthens the material at the shell’s most stressed regions. A drawn shell resists dents and vibration better than the same shape cut from soft bar stock.
Cost curves. At tens of thousands of pieces and beyond, amortized tooling makes drawn parts dramatically cheaper per piece. For a sensor program shipping for years, this is usually the deciding factor.
Where it doesn’t
Prototypes and tiny lots. If you need 50 housings next week, machining wins — no tooling, no waiting. Many customers prototype machined, then switch to drawing for production; we can advise on designing the part so the transition is seamless.
Very large diameters. Beyond what presses and transfer systems handle economically, welded shells take over — for drawn seamless tube work we stay within the range where drawing keeps its advantages.
Wildly non-rotationally-symmetric parts. Deep drawing loves round and square. Extremely irregular geometries may need machining or fabricating — or a drawn body with machined features added, which is often the best of both worlds.
The hybrid answer most buyers land on
The most cost-effective sensor housings are usually drawn bodies with machined critical features: the shell gets its strength and seam-free economy from the press, while threads, hexes and joint faces get CNC accuracy only where they are needed. Our hex head and weldable housings are built exactly this way.
Bottom line
| Your situation | Our recommendation |
|---|---|
| Production volumes, round/square shell | Deep draw |
| Prototype or first article | Machine now, design for drawing later |
| Very large diameter, low volume | Welded construction |
| Deep shell + threads/hexes | Drawn body + CNC features |
Unsure which side of the line your part falls on? Send the drawing with annual volumes — our team reviews process selection with every quote, at no charge, and we will tell you when deep drawing is not the answer.
Related reading: SS304 vs SS316 for sensor housings · our deep drawn sensor housing case study · the full custom deep drawn parts program.