Bio-AMD are a medical equipment manufacturer, who approached us to produce the tooling and injection moulding for medical diagnostic microfluidic test strips. These were to be used in their new blood analysis machine.
Dudley Associates were informed that these strips needed to have channels for blood to flow through via capillary action. Bio-AMD would then place particles into the sealed channels before the blood analysis would be undertaken by the machine.
Further to this, a requirement was that the strip would need to lie perfectly flat in order to retain the blood within the channels.
As with all medical devices and equipment, rigorous testing would need to be undertaken and the highest quality maintained due to the nature and safety levels required.
Because of this, certain considerations needed to be accounted for, which included the following:
- The material of the tool which would produce a completely flat and even surface.
- Due to the degree of accuracy required for this part, would standard tool machining methods be adequate?
- Would the channels can be sealed perfectly and avoid any leakage of blood?
From this, Dudley Associates were able to identify that we would need to use steel to make the tool rather than aluminium due to steel producing a smoother and better finish. It also has only hard alloys and so no pitting would occur.
We also decided to change the way we machined this particular tool. It was decided that we would use Electrical Discharge Machining (EDM), or more commonly known as spark eroding.
Lastly, we needed to address the issue of channels uniformity to enable perfect seal . Due to the design of this product, the injection moulding process would create a weld line, where two flows meet. To prevent this, and any leakage, we needed to vary and experiment with several parameters such as holding pressures, injection pressures, cooling times, holding times, temperature of the tooling and melt.
These testing have resulted in Dudley’s being able to achieve a reduced weld line and ultimately, no leakage and a successful product.