Laser-Cut Enclosure Blanks and Chassis Parts

A box starts as two or three flat blanks

An enclosure that arrives as a finished U-channel with a lid, or a chassis tray with a folded lip, began as flat blanks: one DXF per piece, each carrying its connector cutouts, vent pattern, hardware holes and bend lines. A small controls box can be two blanks, a base with two or four bends and a cover with two, joined by PEM nuts in the base and screws through the cover. A tray can be one blank with a front lip, side flanges and a slotted floor. Each blank is cut flat, bent to the angles and flange lengths on the print, fitted with hardware, finished and inspected as one part, so the quote covers the box, not a pile of operations.

This page covers the formed sheet route. A machined enclosure or housing is a different part: milled from solid when the print needs thick walls, an O-ring groove, a pocket or a sealed face. A formed sheet box suits controls, instruments, power supplies and test gear where the walls are sheet and the joints are hardware or a hem. The electronics enclosures industry page shows where each route fits; if the print could go either way, the quote says which and why.

Materials: 5052 for formed boxes, cold-rolled steel for powder coat, 304 stainless

5052-H32 is one of the four most common aluminum grades sold as sheet, and Wikipedia lists electronic chassis among its common uses; it keeps good formability, while 6061-T6 is stronger but not as formable (source 1). A trade-press design column goes further: 6061-T6 is very difficult to bend, and 5052-H32 bends in about the same way as mild steel (source 2). The inside radius is quoted as drawn, with a note if it won’t form. For an enclosure, that means 5052 for the folded parts and 6061 only for a flat faceplate that gets tapped or machined. Anodizing on laser-cut aluminum is quoted with the cut parts; the laser-cut aluminum page carries the grade notes. Other alloys and plastics quoted on request. Name the grade on the print.

Cold-rolled steel suits a powder-coated chassis. A Products Finishing answer says hot-rolled steel can be much harder to clean for coating and may need an acid or electrolytic clean to remove mill scale, and suggests cold-rolled as the way around it (source 3), so a chassis print names a cold-rolled sheet such as 1008. Name the material and thickness on the print. Of the three stainless sheet grades Wikipedia lists, 304 is the most common and keeps its formability, and 316 has more corrosion resistance (source 1); localized attack is most common where chloride is present, and higher chloride levels call for more highly alloyed grades (source 4). Its cleanability, strength and corrosion resistance have led to its use in food processing plants (source 4). Stainless boxes are left bare, or passivated when the print says so. Name passivation per ASTM A967 on the print; name citric or nitric only if your spec requires one (source 5). The 304 vs 316 page covers that choice.

Cutouts, vents and the hole-to-bend rule

Sheet metal stretches as it bends, and the tooling and the grain direction help decide whether it stretches or cracks (source 2). A hole cut flat close to a bend can go out of round as the metal forms; PennEngineering’s tech sheet on fasteners near a bend says holes should be made after bending for that reason (source 6). So connector openings and vent slots are positioned from the bend line on the print, not from the edge of the blank. A D-sub or USB cutout that must sit closer is made after forming as a secondary machining step, or the flange is lengthened; the quote flags either case rather than moving the hole.

Where two flanges meet at a corner, the flat pattern needs a corner treatment: the flanges can overlap, underlap or butt, and the example part in that column carries bend relief cuts (source 2). Draw the treatment on the blank at each such corner, and the quote flags a corner that has none. Vent patterns are drawn as slot arrays or hole grids with the open area you need. Connector cutouts follow the connector maker’s panel-cutout drawing, and the panels and faceplates page covers the flat front and rear panels that carry most of them.

PEM nuts, standoffs and studs in the blank

Self-clinching hardware turns a thin blank into something a screw can thread into. PennEngineering publishes a sheet hardness limit for each nut type in its catalog listing: types S and SS at HRB 80 or HB 150 or less, types CLS and CLSS at HRB 70 or HB 125 or less, and type SP, an age-hardened A286 stainless nut, at HRB 90 or HB 185 or less, with the mounting hole toleranced +0.003/-0.000 in (source 7). Its installation guide adds that a 300-series stainless fastener is not to be installed into stainless sheet (source 8). A 304 box therefore takes a different type from a 5052 or cold-rolled one; the hardware insertion page goes through which type suits which sheet. Put the PEM part number and its location on the print, and the right hole is cut for it.

The order of operations goes on the print. PEM’s guide says not to install steel or stainless steel fasteners in aluminum panels before anodizing or finishing, and not to install a fastener on the pre-painted side of a panel (source 8), so an anodized aluminum box takes its hardware after the finish. For powder coat, PEM lists thread masking plugs that protect threads from paint and powder coating processes (source 9), which is one route when the hardware goes in before the coat. Standoffs carry a board off the floor of the box at a set height, studs give a blind fastening point for a lid, and nuts take the cover screws. Hardware near a bend has to sit outside the bend radius (source 6); the same bend rules on a smaller part are on the bent brackets page.

Finishes, masking and grounding notes

Powder coat is quoted on steel, stainless and aluminum, anodize on aluminum and passivation on stainless, and each is quoted with the cut parts, not as a finish-only job on a part you already have. The coat adds film on every face it covers, and each powder has its own thickness range on its technical data sheet (source 10), so clearance holes for cover screws are drawn with the coat in mind, and a tapped hole in a coated part is either chased or masked, whichever the drawing says. The finishing page and the powder coating service page cover how each finish is called out.

Grounding and shielding are drawn, not assumed. The anodic layer is insulative (source 11), so a print that needs a ground path on an anodized box masks a pad around a stud or hardware. On a powder-coated box, a grounding stud or a masked bare patch is shown on the drawing in the same way. Where a design calls for EMI shielding, the print shows the flange overlaps and any masked contact areas. A finish called out on the print is quoted with the part. Masking is quoted as drawn, and the quote flags any area where the finish and a hardware callout conflict. The surface finishes hub explains what each finish is.

Inspection, and what to send

Every part inspected against your print before it ships. On a formed enclosure, the print’s callouts are the bends, flanges, cutouts, hardware and finish, and the cosmetic faces it marks. If a part doesn’t match the print, it’s remade or credited.

Send a STEP of the formed part, a DXF of each flat blank if you have them, and a PDF print with material and grade (5052-H32), thickness as a decimal, bend angles, inside radii and bend direction, flange dimensions, hardware part numbers with locations, finish and color code, masking, and which faces are cosmetic. A STEP alone is enough to quote; the flat pattern is confirmed with you before cutting. With no CAD model or drawing, a dimensioned sketch, a new sample part or photos are enough to start; the CAD work is then quoted as its own line, and the quote lists anything missing. A fully dimensioned 2D PDF is quoted without a CAD line. The file guide for laser cutting shows what a complete drawing includes, and the quote form takes the whole package, files first. Ask for more than one quantity, such as 1, 25 and 100, and the quote shows each. There is no minimum: one piece to production runs of 10,000, and one box is a normal order. A person quotes in 24-48 hours, with lead time quoted per job and rush available.

Sources

All accessed 4 October 2026. Where a figure here differs from your print, the print governs.

1. Wikipedia, “Sheet metal”: en.wikipedia.org/wiki/Sheet_metal (5052-H32 among the four most common aluminum sheet grades, good formability, electronic chassis among common uses; 6061-T6 stronger than 5052 but not as formable; grade 304 the most common of the three stainless sheet grades listed, with good formability; grade 316 more corrosion resistance than 304).

2. Gerald Davis, “What to know about sheet metal bend radius and minimum flange”, The Fabricator, 5 August 2017, updated 1 February 2023: thefabricator.com (sheet stretches when it bends and can crack depending on tooling and grain direction; 6061-T6 very difficult to bend, 5052-H32 bends about like mild steel; flange corners overlap, underlap or butt; the example part carries bend relief cuts).

3. David S. Peterson, “Steel Pretreatment Prior to Powder Coat”, Products Finishing, 1 April 2003: pfonline.com/articles/steel-pretreatment-prior-to-powder-coat (cleaning hot-rolled material can be much more difficult and may need an acid or electrolytic clean to remove mill scale; the answer asks whether the parts could all be made from cold-rolled steel). A reader question and answer, no employer named.

4. Wikipedia, “Stainless steel”: en.wikipedia.org/wiki/Stainless_steel (localized corrosion most common in the presence of chloride ions, higher chloride levels require more highly alloyed stainless steels; cleanability has prompted use in pharmaceutical and food processing plants).

5. ASTM International, A967/A967M-25, “Standard Specification for Chemical Passivation Treatments for Stainless Steel Parts”: store.astm.org/a0967_a0967m-25.html (Active, last updated 24 January 2025; nitric acid and citric acid immersion and electrochemical treatments). Referenced, not reproduced.

6. PennEngineering, “PEM REF / C/L TO EDGE”, tech sheet, April 2019: pemnet.com/wp-content/uploads/sites/2/2022/06/CLtoEdgeRev419.pdf (holes should be punched after bending to prevent the hole going out of round; the fastener must sit outside the bend radius on flat sheet). Plain text because the publisher sells fasteners.

7. PennEngineering, catalog listing for self-clinching nuts, types S, SS, CLS, CLSS and SP: catalog.pemnet.com/viewitems/nuts-types-s-ss-cls-clss-cla-sp/self-clinching-nuts-types-s-ss-cls-clss-sp-unified (S and SS HRB 80 or less and HB 150 or less; CLS and CLSS HRB 70 or less and HB 125 or less; SP age-hardened A286 stainless, HRB 90 or less and HB 185 or less; hole tolerance +.003 -.000). Undated. Plain text because the publisher sells fasteners.

8. PennEngineering, “Self Clinching Nut Fastener Installation Do’s And Don’ts”: pemnet.com/products/engineering-guides/self-clinching-fastener-installation-dos-and-donts/ (do not install steel or stainless steel fasteners in aluminum panels before anodizing or finishing; do not install a fastener on the pre-painted side of the panel; do not install a 300-series stainless fastener into stainless sheet). Undated. Plain text because the publisher sells fasteners.

9. PennEngineering, PreTect thread masking plugs, product page for S-440-1ZI-TP: pemnet.com/products/product-finder/s-440-1zi-tp/ (plugs reduce labor and protect threads from paint and powder coating processes; fasteners ship with plugs in place). Footer marked © 2026 PennEngineering. Plain text because the publisher sells fasteners.

10. Rodger Talbert, “Proper Coating Thickness”, Products Finishing, 1 November 2013: pfonline.com/articles/proper-coating-thickness (each powder has a thickness range on its technical data sheet; byline names no employer).

11. Wikipedia, “Anodizing”: en.wikipedia.org/wiki/Anodizing (the anodic layer is insulative).

12. Tim Heston, “Reasonable tolerancing for press brake bending”, The Fabricator, 11 September 2018: thefabricator.com (variation in sheet thickness changes the bend angle; each bend adds its own variation to a dimension that crosses it).