Machine guards sit in the worst possible environment for a thin sheet part: they get hit, they flex, they are hinged and repeatedly cycled, and they are expected to keep people out of a moving mechanism. That combination rewards a small number of deliberate design decisions more than anything else.
| Fixed perforated guard panels | Cold rolled steel 1.5-2mm, powder coated |
| Hinged access doors | Steel 2mm with welded frame, piano hinge |
| Aluminium inspection windows | 5052 or polycarbonate glazing frame |
| Machine base frames | Steel 3-6mm, welded and dressed |
| Cable and ducting covers | Steel or aluminium 1.5-2mm |
| Bolt-on wear panels | Hardened or stainless steel, replaceable |
| Batch range | 1-2,000 pcs |
| Tolerance scheme | Cut +/-0.05mm, hinge mounting faces +/-0.2mm |
| Documents | FAI report, EN 10204 3.1, coating record |
| Finishing | Powder coat, e-coat, hot-dip galvanizing |
| Lead time | Prototype 5-7 working days, batch 2-3 weeks |
| MOQ | 1 piece |
Four things decide whether a guard does its job, and all four are settled on the drawing. First, stiffness: a 1.5mm panel across a 600mm span will flex under a knock and bow out of its frame. Adding a return flange on the back edge costs nothing and turns a floppy panel into a rigid one. Second, hinge and latch geometry, because the mounting faces have to be flat enough that the door seats, or the gap will never be even. Third, the fixings: self-tapping screws into a thin edge strip will work loose under vibration, and a welded boss or a rivnut costs almost nothing.
Fourth is the finish and its edge condition. A powder coated guard looks good and protects well, but the coating does nothing for the raw cut edge underneath, and on an outdoor guard that edge is where corrosion starts. If the guard sees weather, say so at RFQ stage: hot-dip galvanizing handles bare steel properly, and edge sealing matters more than most people expect. Where a guard carries a safety marking plate, state that the marking area must stay flat and uncoated.
| Component (IT / EN) | Typical material | Process | Typical batch |
|---|---|---|---|
| Fixed perforated guard panels | Cold rolled steel 1.5-2.0mm | Laser cut + bend + powder coat | 50-2,000 |
| Hinged access doors | Steel 2mm + welded frame | Laser cut + bend + weld + powder coat | 10-500 |
| Inspection window frames | 5052 aluminium 2-3mm | Laser cut + bend + anodize | 20-600 |
| Machine base frames | Steel Q235 3-6mm | Laser cut + bend + weld + finish | 10-300 |
| Bolt-on replaceable wear panels | Steel 4-6mm | Laser cut + CNC machining | 20-400 |
| Cable and ducting covers | Aluminium 1.5-2mm or steel | Laser cut + bend | 50-2,000 |
Guards are often part-painted and part-bare, with specific faces left uncoated for markings or contacts. Mark those faces on the drawing; they will not be inferred reliably.
The standard flow: drawing review and quotation within 48 hours, first samples in 7–15 days, first article inspection and approval, then series production against the approved reference. Tooling, program revisions and inspection records are kept on file so that call-offs remain consistent with the approved first article.
Engineering changes — material substitutions, tolerance updates, plating or packaging changes — are handled as controlled changes against the same records.
DIN ISO 2768-mK applies as the default tolerance scheme for unspecified dimensions. EN 10204 3.1 inspection certificates are standard for metallic parts, First Article Inspection supports the approval step, and RoHS/REACH declarations are available where required. Plating, cleanliness and packaging requirements are confirmed per drawing.
How thick should a machine guard panel be?
Thickness alone is a poor proxy for stiffness, which is what actually matters. A 1.5mm panel spanning 600mm flexes noticeably; the same panel with a 20mm return flange on the back edge is rigid. If a panel is being hit, bent or repeatedly cycled, the flange is usually cheaper than the extra sheet. Where the panel spans more than about 500mm between frame members, treat stiffness as a design question rather than a thickness question.
What is the right finish for an outdoor machine guard?
For bare structural steel in weather, hot-dip galvanizing. For steel that will be painted, powder coating over a clean surface. The point people miss is the laser cut edge: the zinc burns off there during cutting, so a galvanized guard has a bare steel edge that will start rusting. Specify edge sealing or coating of the cut edge, and the guard will last as long as the rest of the part.
Can you supply flat mounting faces for hinges and latches?
Yes, and on a guard it is worth specifying. Hinge and latch mounting faces need to be flat enough that the door seats evenly, which on a formed part means either a machined face or a well-supported flange. Rather than specifying a flatness figure and hoping, the more reliable approach is to say which faces carry fixings and let us propose the construction that achieves it.
Do you make guards that comply with guarding standards?
We manufacture to your drawing and your specification. Where a guard is part of a machine that needs to meet a particular guarding standard or a risk assessment, the design is normally the responsibility of the machine builder or their safety engineer, and we build to the dimensions and fixings they specify. Tell us the standard the assembly has to satisfy and we will flag any geometric feature that tends to cause trouble in assessment.
Can replacement panels be supplied years later?
Usually yes, and it is worth arranging deliberately when you first order. Keep the flat pattern and the material specification on file with a revision number, and reorders go to the same process. The alternative is a part redesigned years later, laser cut from a different grade with no certificate trail, which is how guards quietly stop matching the machine they belong to.
Send your drawing — Sinbo Precision will review material, tolerance scheme and batch plan and return a quotation within 48 hours. Samples in 7–15 days.
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