Datum Limited, located in Derby, UK are an established engineering company with roots firmly in the foundry industry with the supply of Pattern & Tooling which forms a major part of its business activities as well as being market leaders in the supply of Phenolic GRPh/GRP products.
The Datum Pattern and Tool Shop operates out of 12000 sq. ft. facility and offers full CAD/CAM solutions from data origination through to CNC machining operations. Datum also offer the traditional manufacture of Patterns and Models with a highly skilled workforce producing in wood, metal, resin and polystyrene and has considerable experience with Impellers & Pump Casings.
Recently Datum were asked to produce new pattern equipment for a 1950’s Impeller that had minimal information in the form of a very poor drawing with no Blade sections and a very worn casting that had spent many decades in the water with its surface finish in very poor condition.
From scanned data, generated using the company’s GOM ATOS Compact Scan 5M structured light scanning system, it was discovered that the Impeller casting was actually oval and not one blade was the same size and profile. The original part would have been produced by hand and the pattern equipment shaped and carved to a drawing section.
The performance of the Impeller would have been adequate for the use in the 1950’s but the balance and noise from the rotating part would have been sub-standard for today’s expectations.
The poor surface finish of the casting, after decades immersed in water, transferred into the collected scan data and needed an element of smoothing to be undertaken. “We chose one of the best condition blades and used this data to produce a new 3D CAD form by cladding the worn scan data with new surfaces” comments Datum Director Paul Nelson “Using the Impeller scan section we then created a truly concentric form with the same number of blades but at exact centres. Pattern & Tooling design was then created to ensure all core assemblies fitted together with correct clearances, added machining stock & draft tapers before submission to the customer for approval.”
“Core assembly worked well with all cores locating together perfectly with correct clearances and passing flow analysis of the solid 3D CAD model ensuring correct feeder & runner system design prior to moulding. The end result being an excellent new impeller casting with ‘spot-on’ integrity and once fettled and machined a truly concentric smooth running Impeller delivered that was substantially more efficient than the old casting and a lot quieter” confirmed Paul Nelson.
For more information: www.datum-patterns.co.uk