Mobility aids
Assistive device components supplier — cast aluminium
For an assistive device components supplier, the core job is load-bearing brackets for wheelchairs and walking aids: parts that carry a person every day for years, yet keep the device light enough to lift into a car.
Common failure points
- Weight and strength are conflicting requirements in the same part
- The load is cyclic — fatigue, not ultimate strength, decides service life
- A pore in a loaded section is a crack initiator, not a cosmetic defect
- Traceability and change control, because the customer holds the CE mark
- Cleaning agents, urine, winter roads and salt water attack the surface
- Framework agreements give long, stable series — and an obligation to supply for years
Why casting
A mobility aid is a structure of tubes and profiles held together by fittings. The fittings must meet tubes at several angles, carry bending moment and provide fixing points — complex 3D geometry in moderate series. That is the classic casting, and the alternatives lose: sheet fabrication puts welds where the load is highest, and machining from billet costs too much per part once the series reaches a few thousand.
What the industry needs
Load-bearing brackets and fittings in wheelchairs, rollators and walking aids: frame mounts, seat and back mounts, hinges, adjustment fittings and wheel bearing housings. Parts like these are usually die cast in aluminium, or gravity die cast and heat treated where the strength requirement demands it. One of them, a load-bearing bracket die cast in aluminium, is among our product examples.
What makes the requirements special
Weight is not cosmetic here. The user often has to lift the device into a car or up a flight of stairs. Every hundred grams is a real difference in daily life. At the same time the part has to carry a person. That is exactly the conflict aluminium exists for: a third of the density of steel, with sufficient strength when the design is right.
This is also why “positive product criticism” bites hardest in this segment. Removing metal where the stress is low and adding a rib where the bending moment is high gives a lighter part that is simultaneously stronger. That is not a saving — it is a product improvement for the end user.
Fatigue, not ultimate strength. A wheelchair bracket does not fail from a single overload. It fails after tens of thousands of load cycles, starting at a pore or a sharp internal corner. Freedom from porosity in loaded sections and radii in every transition are therefore the two most important requirements on the drawing.
Traceability. Most walking aids and manual wheelchairs are medical devices in the lowest risk class, and the customer is usually the manufacturer who holds the CE mark. That manufacturer still needs documentation down the chain: which alloy, which batch, which process, and notice before anything changes. A supplier who cannot provide that leaves a hole in the customer’s technical file.
Surface and environment. Mobility aids are cleaned with disinfectant, taken out on salted winter roads and left outdoors. The surface treatment has to survive use, not just the showroom.
Why we fit
- We have supplied parts like these. A load-bearing bracket for the mobility aid industry, die cast in aluminium, is one of our product examples.
- Both casting methods. We choose gravity die casting and heat treatment when tensile strength decides, and die casting when the wall is thin and the series large.
- Machining in house. Hinge bores and seating faces are drilled and milled in the same building where the part is cast. The part does not travel.
- Stable series suit our model. Framework agreements give long runs, and long runs are exactly what contract manufacturing with customer-owned tooling is built for.
What has to be clarified
We are a component supplier, not a medical device manufacturer. The CE mark and the technical file are yours.
Which documentation you need from us, such as first article inspection, a measurement report, melt traceability and notice of changes, is settled in the enquiry. For a load-bearing part in a mobility aid those are the decisive questions, and you will get a straight answer to them before you get a quotation.
Case studies from this industry
Cast brackets made to drawing
Bracket for the mobility aid industry
A load-bearing bracket, high pressure die cast in aluminium, for wheelchairs and walking aids. The part must be light enough for the user to lift the device, and strong enough to carry the user.
Mobility aids
Assistive device components supplier: the part carries a person, every day.
Three things we look for on the drawing
Where the load actually runs
Mark the load path. We put metal where the stress is and take it away where it is not. The result is a lighter and stronger part at the same time.
Internal corners
A sharp internal corner in a cyclically loaded part is a fatigue crack waiting to start. Radii cost nothing in casting.
Which sections are critical
Tell us which sections cannot tolerate porosity. Then we can place gates and overflows so the metal solidifies the right way in exactly that place.
Send the bracket and we will find the grams
Mark the load path and the critical sections. We will tell you where metal can come out without making the part weaker.
Send the drawing
We look at the part and the requirements before we work out a price, and tell you if casting is not the right method.