These two parts get treated as the same job, and the material logic is opposite. A guard has to survive a blade strike and a drop, so it is polycarbonate. A display stand has to disappear visually, so it is acrylic. Get it backwards and one wastes money while the other fails in service.
On drone projects the problems cluster around material choice and how the part is fixed.
Acrylic takes roughly 1/200th the impact energy of polycarbonate. A guard has to be PC, at least 3 mm, and its mounts have to collapse rather than hold rigid — a rigidly fixed guard passes the whole impact load into the arm.
A base-mounted stand covers the gimbal and landing gear. A side cantilever with a small contact foot and clear silicone pads makes the airframe appear to float, with nothing visible in orthographic view.
Under sustained high-frequency vibration the fixing holes become crack initiators, usually within three to six months. Rubber bushes, larger washer area, or a floating mount that allows a little movement all extend life.
EPE is cut to the arm profile with 2 mm clearance. Too tight and the arm is under load for the whole journey: it deforms slowly, looks fine on opening, and flies out of trim.
Flight parts and display parts are made to different rules, with material set per station. Related capability sits on the Industrial & machinery page.
Drone work is the clearest case in the whole plant where one material cannot serve the whole assembly, and where choosing the wrong one is a safety issue rather than a cost issue. The split is simple and it is not negotiable: anything that can be hit is polycarbonate, anything that only has to be seen through is acrylic.
Acrylic absorbs roughly 1/200th the impact energy of polycarbonate before it fails, and it fails by shattering into sharp fragments. A propeller at speed will go through a 3 mm acrylic guard and the fragments become the injury. There is no thickness at which acrylic becomes an acceptable propeller guard — the failure mode, not the strength, is the problem. A polycarbonate guard at the same thickness will deform and hold.
Everywhere the job is display, inspection or transport. A display stand that presents an airframe on a trade stand, a transport cradle that holds a folded drone in a case, a test-bench window that lets an engineer watch a bench run, a ground-station panel that has to be read in daylight — all of these are acrylic, and acrylic is better than polycarbonate here because it is clearer, harder, and does not yellow at the same rate.
| Part | Material | Reason |
|---|---|---|
| Propeller guard | Polycarbonate, 4–6 mm | Must absorb impact and deform, not fragment |
| Airframe display stand | Cast acrylic, 5–8 mm | Clarity and edge finish are the whole point; no impact exposure |
| Transport cradle | Cast acrylic or EVA-lined acrylic | Locates the airframe without point loading the arms |
| Test-bench window | Cast acrylic, 6 mm, annealed | Vibration resistance comes from annealing and from slotted fixings, not thickness |
| Ground-station panel | Cast acrylic, 3–5 mm | Read in daylight; UV-stabilised grade for field use |
A test-bench window that cracks is almost never too thin — it is over-constrained. A panel bolted rigidly on four sides to a vibrating frame has nowhere to move, so the stress concentrates at the holes and a crack runs between them. Slotted holes with a compressible washer, plus annealing after machining, is what stops it. We apply that as standard on any panel that mounts to a running machine.
The material split drives the cost more than anything else in this sector, because polycarbonate runs roughly 1.4 to 1.8 times the price of cast acrylic for the same thickness, and it is slower to machine cleanly. On a mixed order — guards plus stands plus cradles — expect material to be 25–35 percent, machining 30–40 percent, and edge and finish work 10–20 percent.
There are two sensible ways to take cost out. First, keep polycarbonate to the parts that genuinely need impact resistance; specifying the whole enclosure in polycarbonate "to be safe" adds 20–30 percent for no safety gain on a display stand. Second, use one sheet thickness across a family of parts so they nest together — a drone kit with four thicknesses pays for four setups and four offcut piles.
What we will not do is supply an acrylic propeller guard, even when asked, without stating in writing what it will do on first contact. It is the one place in this plant where we would rather lose an order than ship the part.
| Item | What we need | Why it changes the price |
|---|---|---|
| Part function | Guard, display, transport, or inspection | Decides acrylic versus polycarbonate, a 1.4–1.8x material difference |
| Airframe drawings | Arm positions and motor spacing, or the model file | A cradle that point-loads an arm will crack it in transit |
| Prop size and RPM | For any guard | Sets the polycarbonate thickness; acrylic is not quoted for this position |
| Mounting frame | Whether the panel bolts to a vibrating frame | Vibration resistance comes from slotted holes and annealing |
| Field use | Indoor or outdoor, and UV exposure | Outdoor panels need a UV-stabilised grade |
We will not quote an acrylic propeller guard. If the position can be hit, the part is polycarbonate, and we would rather explain that once than ship something that fails on first contact.
Flight and display parts inspected on separate lines; guards ship with material documentation.
Not advisable. Acrylic has about 1/200th the impact strength of polycarbonate, so a thrown blade goes straight through — and the fragments are sharp. Guards, bumpers and impact faces are always PC; clear display and dust covers are where acrylic belongs. The two look similar and cannot be told apart by feel, so always ask for the material certificate.
Three things together: keep the contact area small (point contact rather than a face), run the structure to the side or behind, and pad the contact point with clear silicone. Above 3 kg an auxiliary support is still needed, but it can be a thin rod kept in shadow so it drops out of a front-on photograph.
Display parts, no. Flight parts, yes: acrylic is around 20% heavier than the same volume of polycarbonate, and at the end of an arm that changes the moment of inertia, so the machine needs rebalancing. That is the second reason flight parts are PC — weight as much as impact.
Yes. The insert is cut as a machined grid with each cradle sized 2 mm oversize and lined with EVA, so arms are located without point loading. The critical detail is that the cradle supports the body rather than the arms, because a folded arm taken on a hard foam edge will crack at the hinge. We ask for one airframe or its drawing before cutting.
No. Acrylic is the wrong material for any part that takes landing load — it is brittle under impact and fails by shattering. Those parts belong in carbon, glass-filled nylon or polycarbonate. What we make for this sector is the display, transport and inspection side, where clarity and finish are the requirement rather than toughness.
