Most prototype shops build exactly what the file says and hand it back. That works right up until the part is approved and someone has to make a hundred of them — then the bend reliefs, the tolerance stack-up, the hardware choices and the finish callouts all become expensive. MJM approaches sheet metal prototyping differently. Before we cut anything, our engineering and estimating team reviews your model the way a fabricator reads it: flat pattern, bend sequence, tooling access, weld access, hardware, finishing and inspection.

If we see something that will fight the process — a flange too short to hold in a press brake, a bend radius that will crack the material, a tolerance that only a secondary operation can hold, a fastener that could be a formed feature instead — we tell you, explain why, and suggest an alternative. Most of the time the change is small, the part still does exactly what you designed it to do, and the cost comes down noticeably. That feedback is included in the quote, not billed as engineering consulting.

The result is a custom metal prototype you can actually take to production. Same building, same machines, same programs, same people — whether you need one proof-of-concept part or a recurring low-volume production run. We have been building sheet metal parts in Miami Gardens since 1979, and the shop is set up so that scaling up is a scheduling decision, not a re-engineering project.

This is the part customers tell us they value most. Here is what we actually look at when your design for manufacturability (DFM) review comes back:

Bend radii and material behavior: A radius that is too tight will crack aluminum along the grain or leave a visible stress line on a cosmetic face. We recommend a radius the material will accept and, when it matters, orient the blank so the bend runs across grain.

Flange lengths and tooling access: Every press brake needs enough flange to hold the part safely and enough clearance for the punch to come down. Short flanges, tall boxes and returns that trap the tool are the most common reasons a drawing has to change — we catch them at quote time and show you the minimum that works.

Bend reliefs, hole placement and distortion: Holes and slots too close to a bend line pull oval. Missing reliefs tear at the corner. Small changes here remove secondary operations and scrap.

Tolerances that earn their cost: Not every dimension needs to be held tight. We identify which callouts drive inspection time and secondary machining, and ask whether the function really requires them — often one or two features do and the rest can open up.

Tolerance stack-up across assemblies: Parts that fit perfectly in CAD can bind in steel once each bend carries its own tolerance. We look at the assembly, not just the piece part, and suggest where to add adjustment — slotted holes, a floating bracket, a self-locating tab.

Welds versus formed features and hardware: A welded corner that could be a formed one saves fixturing, distortion and finishing labor. Conversely, self-clinching hardware often beats a tapped hole in thin material. We suggest the swap when it makes the part cheaper or stronger.

Material choice and thickness: Sometimes a lighter gauge with a formed stiffening rib outperforms a heavier flat panel, and costs less. Sometimes a different alloy forms better and finishes cleaner. We will tell you when a substitution is worth considering — and when it is not.

Nesting, yield and part layout: How a part sits on the sheet drives material cost. Minor outline changes can lift yield significantly on a production run, and we will show you the difference while the design is still easy to change.

Finishing and cosmetics: Masking, grain direction, weld blending, hardware installed before or after powder coat, silkscreen and label placement — the details that decide whether the finished prototype looks like a product or a shop part.

You always make the final call. We send back notes, a marked-up view where it helps, and a price for the design as drawn alongside the price with our suggestions — so the trade-off is a decision, not a surprise.

Enclosures, housings and cabinets: Proof-of-concept electronics enclosures, control panels, NEMA-style boxes, rackmount chassis and instrument housings — cut, formed, welded, hardware-installed and finished as one job.

Brackets, frames and chassis: Mounting brackets, weldments, sub-frames and structural chassis for equipment builders and robotics developers, where fit and iteration speed decide the schedule.

Panels, covers, doors and skins: Cosmetic and functional panels with formed returns, louvers, cutouts, countersinks and finish requirements that have to look right the first time.

Machined-look sheet metal alternatives: Parts originally drawn as machined blocks that can be formed and welded for a fraction of the cost — one of the most common savings we find in prototype review.

Replacement and reverse-engineered parts: Bring in a broken or obsolete part and we will measure it, model the flat pattern and build a fit-for-purpose replacement.

Pilot and bridge production: The short runs that carry a product from prototype approval to full production — ones to hundreds of parts, repeat orders welcome.

Materials: Aluminum (5052, 6061, 3003), cold-rolled and hot-rolled steel, stainless steel (304, 316, 316L), galvanized and galvannealed steel, copper, brass, beryllium copper and titanium — in gauges from thin decorative stock up to heavy plate.

Cutting: Fiber laser cutting for clean, fast, tooling-free prototype blanks, plus CNC turret punching when a part is full of standard holes, louvers, embosses or extrusions.

Forming: CNC press brake forming with offline programming and bend simulation, plus plate rolling for cylinders, radii and curved panels.

Joining: TIG, MIG, spot and fiber laser welding for aluminum, stainless and steel, plus self-clinching studs, nuts and standoffs installed in-house.

Finishing: Deburring, graining, powder coating, anodizing, plating, chem film, silkscreen and labeling — coordinated as part of the same job so your prototype arrives finished, not raw.

The hardest moment in a new product is usually the handoff — the prototype came from one shop, production goes out to bid somewhere else, and the part quietly changes. Nothing gets handed off here. The programs, flat patterns, bend sequences, weld fixtures and finishing notes we develop for your first article are the same ones we run on order number two, order number twenty, and every reorder after that.

That has real consequences for cost and schedule. Second orders are quicker because the setup work is done. Per-part pricing improves as quantities rise and nesting gets more efficient. Revisions are controlled — when you release a change, we update the program and note the revision so the parts on the floor match the drawing you approved. And because we run short-run and low-volume production every day alongside larger jobs, you are not competing for attention with a million-piece order.

For customers with ongoing demand we can schedule blanket orders and staged releases, so you hold less inventory and still get parts when your build schedule needs them.

A prototype that does not match its drawing wastes more time than a slow one. Every part gets dimensional inspection against your print before it leaves — verified on Amada Fabri-Vision automated optical inspection and Keyence CMM — with material traceability and first-article documentation available on request. Our AS9100 and ISO 9001 certified quality system carries the certifications demanding customers ask for, and the same discipline applies whether we are building one part or a thousand — without turning your prototype into a paperwork exercise.

MJM has been fabricating sheet metal in South Florida since 1979, from a 44,000 sq ft facility in Miami Gardens running five Amada fiber laser systems, nine Amada press brakes, nine IPG fiber laser welders and more than 40 major machines on the floor. If you want to see how your part will be built, come walk the shop.