A deep-drawn part starts as a flat disc and ends as a cup: a punch pushes the blank through a die and the metal flows into a shell with one open end, a uniform wall and no seam anywhere. That is what makes a drawn cap lighter, tighter and cheaper in volume than a machined or welded one — and what limits it: the depth a metal will flow to before it tears, and the features a punch can form.
EKINSUN LTD is a custom parts manufacturer that makes deep-drawn parts to drawing: caps, cups, sleeves, ferrules and small housings in steel, 304 / 316 stainless, aluminium and copper, drawn in one or several stages with the diameter, depth, wall and flange the drawing calls for, from single-stage sample tooling to progressive volume. The part table below lists what is drawn; the depth table explains the limit that decides one draw or several; the negative-space table says what is drawn, what is machined and what is turned from tube.
"Sensor housing, 14 mm outside, 32 mm deep, 0.4 mm wall, stainless, closed end, no weld. The machined version costs ten times what the drawn one should."
Depth more than twice the diameter in a thin wall is a multi-stage draw, and a multi-stage draw is a volume part.
| Part | Form | Materials | Features that can be drawn or added | Where it goes |
|---|---|---|---|---|
| Round cap / cover | shallow shell, open one end | steel, 304, aluminium, copper | flange, bead, knurl, hole in the base, embossed logo | trim caps, seal caps, decorative covers |
| Cup / can | deeper shell | steel, 304, aluminium | stepped diameters, domed base, rolled edge | battery cans, capacitor cans, small containers |
| Sleeve / ferrule | thin-walled tube with one end formed | 304, brass, copper, aluminium | flared or crimped end, grooves | cable ferrules, bushings, spacers |
| Sensor / probe housing | long narrow shell, closed end | 304 / 316 | thin wall, closed hemispherical or flat end, thread rolled on the open end | temperature and radar sensors, probes |
| Battery cover / terminal cap | shallow shell with holes | nickel-plated steel, 304 | vent holes, tabs | battery packs, EV connectors |
| Housing / shell | rectangular or round box | steel, aluminium | corner radii, lugs, cut-outs added by a second operation | electronics enclosures, connector shells |
| Insert bushing | thick short cup or ring | steel, brass, 304 | knurl, flange | pressed into plastic housings — see stamped parts |
| Depth compared with diameter | Stages | What happens | Cost shape |
|---|---|---|---|
| Shallow: depth well under the diameter | one draw | the metal flows without thinning much; almost any drawable material | single-stage tooling; cheap from a few hundred |
| Depth about equal to the diameter | one draw, sometimes two | the wall thins near the base; a blank-holder controls wrinkles | single-stage or two-station tooling |
| Depth one and a half to three times the diameter | several draws with re-draws between | each stage reduces the diameter and adds depth; annealing between stages for stainless and copper | progressive or transfer tooling; a volume part |
| Deeper still, thin wall | many stages, ironing | the wall is thinned deliberately by ironing rings | volume only; cans and cartridges |
Material sets the ratio a single draw can reach: soft deep-drawing steel and copper flow furthest, aluminium 6061 in the soft temper draws well, 304 draws well but work-hardens and may need annealing between stages, 316 less far, and hardened or 7075-type alloys not at all. The wall stays close to the blank thickness on the side and thins toward the base corner; a drawing that needs a uniform wall to a tight tolerance is telling us to iron, and ironing is a volume process.
| What you need | In the catalogue? | What we make |
|---|---|---|
| A standard cap, ferrule or end cap in a catalogue size | Yes | Buy it from stock; a catalogue drawn cap is cheaper than any tooling. |
| A round cap or cup in steel, 304 / 316, aluminium or copper, depth up to about the diameter, hundreds to millions | No | Deep-drawn on single-stage tooling for the first batch and progressive tooling for volume. |
| A deep shell — depth two or three times the diameter — in thin wall | No | Multi-stage drawn; a volume part, and we say from what quantity it pays. |
| A cup with a thread, a machined bore or a flatness a draw cannot hold | No | Drawn and then machined, or machined from bar; we quote both. |
| One to fifty pieces of a drawn shape | No | Turned from bar or tube instead of drawn; the price is per piece and the draw tooling is quoted for later — see small machined parts. |
| A rectangular or non-round shell | No | Drawn with a shaped punch where the corner radii allow; otherwise bent and welded, and we say which. |
| A drawn part in 316L, brass, nickel silver or beryllium copper | No | Drawn in the alloy named where it draws; otherwise machined. |
| A drawn part in aluminium 6061 or 7075 | Partly | 6061 draws in the soft temper and is heat-treated after; 7075 does not draw and is machined instead, and we say so. |
| Material | Designation | Where it fits here |
|---|---|---|
| Deep-drawing steel | DC04 / DC05; SPCC-SD | the easiest draw; plated after |
| Nickel-plated steel | pre-plated strip | battery cans and terminal caps |
| Stainless 304 | 1.4301, soft annealed | draws well; anneal between deep stages |
| Stainless 316L | 1.4404 | draws less far; marine and chemical parts |
| Copper | Cu-DHP / Cu-ETP | draws very deep; thermal and electrical parts |
| Brass | CuZn30 / C26000 (cartridge brass) | the classic deep-draw brass |
| Aluminium 6061 | AlMg1SiCu, O temper | light caps and housings; anodised |
| Aluminium 7075 | AlZn5.5MgCu | not drawn; machined where its strength is needed |
| Free-machining stainless | 303 / 1.4305 | the alternative when a handful of cups is turned instead |
A sheet-metal process in which a flat blank is pushed by a punch into a die so the metal flows into a hollow shell with one open end. The wall is formed from the blank itself, so there is no seam and no weld, and the part is lighter and more consistent than a machined or fabricated one in volume.
Roughly to a depth close to the diameter in a good deep-drawing steel, copper or soft aluminium; less in 316 stainless. Deeper parts are drawn in several stages with re-draws, and stainless or copper may be annealed between them. Very deep thin-walled parts are ironed, which is a volume process.
Drawing needs tooling, so the practical minimum on single-stage tooling is a few hundred pieces. For fewer, the same cup is turned from bar or tube and the draw tooling is quoted for when the quantity grows.
Deep-drawing steels, nickel-plated steel, 304 and (less deeply) 316 stainless, copper, cartridge brass and aluminium 6061 in the soft temper. Hardened steels and 7075 aluminium do not draw and are machined.
EKINSUN LTD is a custom parts manufacturer that makes deep-drawn caps, cups, sleeves and housings to drawing in steel, 304 / 316 stainless, copper, brass and aluminium 6061, from sample tooling to progressive volume, and turns the same parts from bar for small quantities, with a quote within 12 hours.
No list price. The tooling is quoted separately from the parts: single-stage draw tooling is modest, multi-stage progressive tooling is an investment recovered over the run. The part price follows material, wall, number of stages and plating. The quote shows the tooling and the piece price, and the machined alternative for small quantities.
Diameter (inside or outside), depth, wall, base radius, open or closed end, material, finish, quantity now and per year. A sample or a photo works. From 1 piece machined, quote within 12 hours.
Deep-drawn caps, cups, sleeves and housings to diameter, depth and wall — sample tooling to volume, quote in 12 hours.