subject: Castings without pattern - A new way to produce iron sand castings [print this page] Castings without pattern - A new way to produce iron sand castings
Nopatech is a new technology developed by Saguenay Foundry. Its purpose is to make very short production runs of gray & ductile iron castings faster and more cost effective by eliminating the need to produce a pattern.
In regular production, patterns are made de create an imprint in a sand mould. Metals are then poured in the "negative" of the part. After cooling, you get a part to the correct dimensions and shape. This technology has been done for hundreds of years to obtain complex shapes that could not otherwise be machine directly in a cost-effective manner.
The problem with patterns is that they are expensive. If you redo the castings dozens or hundreds of even better thousands of time, it can easily be amortized. But in certain situations, one or two castings might be all you need. For instance, prototypes of an unproven design are subject to change after a trial of one or two castings. With a pattern, some change can be made, but not always, so you are always taking a risk.
In this case, a casting that cost 2000$ can require a 5000$ wood pattern do be produced effectively. If you do only one, your casting has cost you 7000$. Nopatech on the other hand might cost you only an extra 1500$ - 2000$ to cast a part without pattern . This is a very substantial gain. The lead time might also go down by half.
To obtain this low cost and fast lead-time, Nopatech benefits from the advance in robotic technologies to machine blank sand moulds directly to the final shapes. Cores can also be done, so there is no limit to the complexity of the final shape. Basically, what can be done with wood patterns can be done with Nopatech.
Also, the quality matches exactly what you get from a casting made with a regular pattern. You reach an average "as cast" RMS figure of 500 and the accuracy of the mould is within 1/16'' of an inch, a precision that compares favourably to pattern-made parts. The size limitations is also the same as any other part done at our foundry, with a 115'' x 115'' maximum flask and a 16,000 lbs gross weight pouring capacity.
