Medical Equipment and Instruments

Why Surfaces, Edges and Fits Matter in Medical Equipment

A surgical instrument is cleaned and sterilised hundreds of times during its working life, and each cycle acts on the metal surface. We machine and mold instrument parts and small components in steels such as 316L and 17-4 PH. Device makers specify these grades for corrosion resistance and mechanical strength. Biocompatibility evaluation and approval of the finished device stay with the manufacturer who integrates the part.

The jaws of a needle holder and the cutting edges of scissor blades open and close under grip force thousands of times. The wear happens along the edge, where the instrument does its work. For these surfaces we make pressed and sintered carbide inserts, which hold their geometry over many cycles.

Lifting columns on an operating table, a hospital bed or a dental chair base move the same load up and down for years and have to hold position at any point of the stroke. How well a cylinder does this depends on its seals and on the surface of the rod that runs through them. We pressure test every cylinder before it ships.

A diagnostic analyser or a dosing module runs one small gear train for its whole service life, and the gears in that drive have to be identical. In metal injection molding the mold forms the tooth profile of a miniature steel gear, and every gear from that mold has the same geometry.

A surgical light or an examination lamp runs an LED source at close range. The heat from the LEDs has to leave the housing before it builds up around the fixture. We die cast the aluminium housing together with its cooling fins, in the same alloys we use for other lighting work. The outer surface stays plain and is easy to wipe down.

Tables, beds, chairs and analysers are built in series, and every unit needs the same part. We keep drawings and tooling on file between batches. Each part ships with a material certificate and a dimensional report for the design record, whether the order is one prototype or a production run.

A table, bed, chair or analyser platform often stays in production for years, and a part ordered today has to match the one made for a unit built several years earlier, down to the mounting hole pattern. For every die-cast, sintered or MIM part we keep the tool drawings, the gate and overflow layout or the injection and sintering parameters, and the process settings on file, and a repeat order is made with the settings approved for the first article. For machined parts we keep the CNC program and the fixture, and a reordered hinge, shaft or bracket has the same dimensions as before.

If a fixture, a lifting cylinder or a housing has no drawing left, send us the part or its dimensions. We measure the geometry on the CMM and quote a replacement before production starts. When the tool or the program is ready and the first article is approved, we run further batches from it with no redesign, for a few units or a full production series.

Medical device regulations, biocompatibility evaluation, sterilisation validation and device approval belong to the manufacturer who builds and registers the finished device. We supply component documentation to the drawing: a material certificate, a CMM dimensional report and test records for the part we made.

Our quality system is certified to ISO 9001:2015. More on inspection stages and equipment: Quality.

Every order goes through three inspection stages. We check incoming material against its certificate, and where the grade matters, for example a stainless steel or a MIM powder lot, we run a spectrochemical analysis. During machining we measure with Renishaw probes on the machine and on a CMM with an error under 3 μm, checked on schedule every 45 machine hours.

Die-cast housings and covers are X-rayed for porosity at mounting bosses and sealing faces before machining. Sintered and MIM parts, instrument jaws, ratchet locks and drive gears among them, are checked for density, hardness and dimensions on every lot, with weight control on MIM green parts as an early warning of a feedstock drift. Carbide jaw and blade inserts are ground to their functional tolerance, tested for Rockwell hardness and checked under the microscope for grain size and binder distribution. Hydraulic cylinders for lifting columns are pressure tested at 1.5× working pressure. The test includes a leak check at every seal and a full stroke with no stick-slip.

More detail: Quality.

What documentation do you supply for medical equipment and instrument parts?

MIM and PM parts, instrument jaws, ratchet locks and drive gears among them, ship with a material certificate for the powder lot and a dimensional and hardness or density report. Die-cast housings and covers ship with a material certificate and a CMM dimensional report. Carbide inserts come with hardness testing and CMM verification. Medical device regulations, biocompatibility evaluation and sterilisation validation stay with the device manufacturer; tell us the documentation your component record needs and we plan the package with the order.

Can you match an existing hinge, cylinder or housing with no drawing?

Yes. Send us the part or its dimensions and we measure the geometry on the CMM before quoting a replacement or a new batch. After the tool or the machining program is built and approved, later batches are made from it with no redesign.

We build the same table, bed, chair or analyser in series. Can you supply it as a batch?

Yes. Once the first part has been quoted and measured against your drawing or your sample, further units run as a batch, with the same certificates and tests on every piece and one setup for the run. For die-cast, PM and MIM parts the drawing and the tooling stay on file, so a repeat order matches the first part with no redesign.

What is the minimum order and the lead time?

A single cylinder is fine, with the same certificates and tests as a series batch. For motors and gears, tell us the quantity and we will quote. Die casting, powder metallurgy and MIM are tool-based series processes, so send us your volumes and we will size the tooling and quote. We quote the lead time with the offer: tooling is built and trialled before the first article, and materials and documentation add steps depending on the part.