Deep drawing
How much wall thickness variation is normal in a deep drawn part?
Answer
Wall section, bore and concentricity: where the three routes separate A drawn housing carries a wall gradient. Material that started at the blank thickness is thinner at the wall than at the bottom, and the thinning is not uniform around the circumference of an eccentric part. That is normal, not a defect, and it is why a drawn housing drawing should say where the wall is measured and what the minimum is at that point. A machined housing has one nominal wall everywhere and holds it by the stiffness of the setup rather than by tool clearance.
Sources
- Motor Housing: Stamped vs Deep Drawn vs MachinedWall section, bore and concentricity: where the three routes separate A drawn housing carries a wall gradient. Material that started at the blank thickness is thinner at the wall than at the bottom, and the thinning is not uniform around the circumference of an eccentric part. That is normal, not a ...
- How To Calculate Blank Size For A Deep Drawn Cup?Calculate the blank twice — once with the classical formula and once by surface area on the mean dimensions — and quote the difference. If the two numbers disagree by more than a few per cent, the bottom radius or the wall thickness is doing real work in your part, and that is exactly the detail the...
- Earing In Deep Drawn Cups: Why The Top Edge Is UnevenHeight tolerance. If the height tolerance on the drawing is tighter than the ear height, the part cannot be made without a trim operation, and that operation belongs in the quoted route. Wall thickness variation. The directions that end up as ears are the directions that resist thinning, so the wall...
- Minimum Wall Thickness in Deep Drawing: Sensor HousingsThree ways wall thickness changes in production Thinning during drawing. Material flows and stretches, so the wall of a drawn cup is not the thickness of the blank. Tool radius, clearance and lubrication decide how much thinning happens and where. Ironing. Where the wall has to be thinned deliberate...
- Drawn Sheet Metal & Deep Drawing: Complete Guide | BalfordRelative wall thickness against position: about 1.00 times nominal at the bottom centre, thinning to roughly 0.85 in the lower wall, then recovering to about 1.05 at the top edge because the flange thickens as its circumference shrinks. 0.80t 0.85t 0.90t 0.95t 1.00t 1.05t 1.10t nominal blank thickne...
- Drawn Sheet Metal & Deep Drawing: Complete Guide | BalfordAllow a trim allowance on the top edge. The drawn edge is uneven because of earing and normal process variation. Prefer a simpler profile over a stepped or tapered one if the function allows it. Each change of diameter can add a draw. Define which diameter is functional. If one diameter can be free,...
What an engineer still needs from you
- material and material condition (grade, temper)
- material thickness, plus the key diameter, height and wall thickness
- tolerances, burr direction and the visual acceptance standard
- annual volume - it decides whether tooling is single-hit, progressive or transfer
- surface finish, and any secondary machining, annealing or plating
Need a DFM feasibility assessment for your project?
Send the engineering drawing (STEP or PDF) with the material grade, thickness and annual volume. Balford engineers then check it against the process window - draw ratio, wall thickness, tolerances, blank and tooling route - and come back with what is feasible and what is not. An answer on this page cannot replace that review.
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This page is an engineering answer, not a quotation and not a dimensional acceptance. It is generated from Balford's published material and held to the verified company fact sheet.