Custom Metal Trays for OEM Equipment: Design & RFQ Guide

Custom metal trays look simple until they have to support equipment, align with slides, drain liquid, protect cables or arrive ready for assembly. Material thickness alone does not determine whether a tray will work. Flange geometry, bend sequence, corner construction, hardware, finish and datum strategy all affect stiffness, fit and production cost.

This guide is for OEM buyers and mechanical engineers sourcing formed trays rather than off-the-shelf storage pans. It explains which decisions belong on the drawing and which are best confirmed through supplier DFM.

What makes an OEM tray different

An OEM equipment tray is normally part of a larger mechanical system. It may carry batteries, electronics, pumps, tools, food-processing components or service parts. That creates requirements a generic pan does not address.

Requirement	Design implication
Slide or rail mounting	Parallel side flanges and controlled hole position
Liquid containment	Sealed corners, drain strategy and corrosion-resistant material
Electronics support	Grounding points, cable access and removable hardware
Heavy component load	Return flanges, ribs, crossmembers or thicker material
Frequent service	Safe edges, handles, labels and wear-resistant finish
Cosmetic installation	Protected show surfaces and controlled weld dressing

Related customer project: Stainless Reagent Boxes: Cleanable Corners and Seams. Related resources: custom sheet metal boxes and trays.

Select material by environment and function

Cold-rolled steel

Cold-rolled steel is economical, stiff and easy to weld. It suits indoor equipment where powder coating or plating can protect the surface. It is often the lowest-cost choice for industrial drawers, machine trays and electronics shelves.

Stainless steel

304 stainless is common for washdown, food, laboratory and corrosion-prone environments. 316 is better where chlorides or aggressive cleaning chemicals are present. Stainless costs more and requires disciplined surface handling, but it can eliminate coating damage as a failure mode.

Aluminum

5052 aluminum is a practical choice for formed lightweight trays because it bends more reliably than 6061-T6. Aluminum reduces weight and naturally resists corrosion, but it needs attention at threaded interfaces and dissimilar-metal joints.

Do not write only “steel” or “aluminum” on the RFQ. State the full grade, temper where relevant, thickness and substitution rules. Our aluminum grade comparison and 304 vs 316 stainless guide cover the material trade-offs.

Build stiffness into the shape

A flat-bottom tray may oil-can or sag even when the static stress is acceptable. Before increasing thickness, consider geometry that raises section stiffness:

• Upturned side flanges and folded returns.
• Downturned edge channels under the load path.
• Embossed ribs or beads in broad flat areas.
• Bolted or welded crossmembers under concentrated loads.
• Rolled or hemmed safe edges where appropriate.
• Shorter unsupported spans through mounting-point placement.

Treat catalog load ratings with caution. A tray carrying a uniformly distributed load behaves differently from one carrying a heavy motor at its center. Give the supplier the real load location, mounting condition and acceptable deflection.

Corner construction options

Corner style	Best use	Main trade-off
Open relief corner	Dry equipment and lowest cost	Does not contain liquid or dust
Tab-and-slot corner	Self-location before welding or riveting	Visible joint and added features
Welded corner	Washdown, containment and high rigidity	Heat distortion and finishing cost
Riveted or screwed corner	Serviceable or low-heat assembly	More hardware and potential leak path
Folded/locked seam	Repeat volume with controlled tooling	Geometry and tooling constraints

If liquid retention matters, specify whether the requirement is splash control, drip containment or a tested leak-tight joint. These are not equivalent acceptance criteria.

Bends, radii and safe edges

Use a consistent inside bend radius where function permits. Shared radii reduce tooling changes and simplify flat-pattern development. Keep holes and slots out of the bend deformation zone unless distortion is acceptable or a relief is provided.

Exposed service edges may need a hem, rolled edge or deburred radius. A hem improves safety and stiffness, but it also creates a narrow pocket that may trap liquid or particles. For clean or washdown equipment, an open return with a controlled edge can be better.

See the minimum bend radius and bend-relief guide for detailed geometry rules.

Hardware and assembly interfaces

Specify how the tray connects to the equipment. Common options include PEM nuts, standoffs, weld nuts, rivet nuts, hinges, drawer slides and captive fasteners. The drawing should identify:

• Hardware manufacturer and part number or an approved equivalent.
• Installation side and orientation.
• Threads that must remain coating-free.
• Required push-out or torque testing.
• Grounding points and masking requirements.
• Mating component and functional datum.

For repeated assembly, locating tabs and slots can reduce fixture dependence. They should locate the parts without overconstraining the tolerance stack. Our PEM hardware insertion guide explains edge distance and installation controls.

Finish selection

Choose finish around the operating environment and functional surfaces.

Finish	Typical tray use	Drawing notes
Powder coating	Indoor steel equipment	Color, texture, thickness and masked areas
Zinc plating	Small steel trays and hardware	Corrosion class and thread protection
Passivation	Stainless trays	Standard, test method and weld condition
Anodizing	Aluminum electronics trays	Type, color and contact masking
Bare/brush finish	Stainless or conductive parts	Grain direction and cosmetic face

Do not apply a coating over electrical contact points, bearing surfaces or tight slide interfaces without allowing for thickness.

Tolerances that actually matter

Tray drawings often become expensive because every dimension receives the same tight tolerance. Instead, identify the interfaces that control assembly:

• Distance and parallelism between slide-mounting flanges.
• Hole position relative to the formed mounting datum.
• Internal envelope around the carried equipment.
• Flatness under mounting or sealing surfaces.
• Door, drawer or adjacent-panel gaps.

Use general fabrication tolerances elsewhere. If the tray is inspected while free and deflects under its own weight, define the inspection restraint or fixture condition.

Custom metal tray RFQ checklist

Include these items before requesting a production quote:

• Formed STEP model and controlled PDF drawing.
• Material grade, temper, thickness and substitution policy.
• Load magnitude, location and allowable deflection.
• Critical datums, interfaces and inspection condition.
• Corner joint and leak or washdown requirement.
• Hardware list with installation and test notes.
• Finish, color, texture and masking details.
• Cosmetic faces and edge-safety requirements.
• Prototype quantity, batch quantity and annual volume.
• Packaging and labeling requirements.

From DFM to repeat production

DRAmetal manufactures custom sheet metal boxes and trays in steel, stainless and aluminum using laser cutting, CNC bending, welding, hardware insertion, finishing and assembly under one production plan. We review the load path, bend access, hardware clearances and finish stack before the flat pattern is released.

Related customer project: Stainless Reagent Boxes: Cleanable Corners and Seams. Related resources: contact page · custom sheet metal drawers and slide-out trays.