GIW Industries, of Georgia, USA, has been making the most of the facilities available to Members of Cti. This has included 3D modelling expertise, CNC patternmaking and an evaluation of the latest Patternless® technology. The results are helping GIW to produce extremely accurate, high quality castings for the slurry pump sector.
GIW Industries is a subsidiary of KSB AG, a global pump and valve manufacturer in Frankenthal, Germany. The company is comprised of two manufacturing facilities, one in Grovetown, Ga. and the other in Thomson, Ga. These foundries and machine shops are used for manufacturing and assembling pumps and for casting a variety of abrasion- and corrosion-resistant alloys and polyurethane elastomers.
GIW became a Member of Cti in the middle of 2000. A tour of the facilities and talks with Cti staff led to three related projects which enabled GIW to benefit from the expertise available in Sheffield.
GIW had recently purchased SDRC Masterseries IDEAs software for 3D modelling of casting designs. They were able to make full use of the many years of experience of Pete Bond, Cti’s casting design engineer, to convert two of their components, a pump casing (1660 x 1520mm) and impeller, from 2D drawings into 3D models. The software’s ‘history tree’ is now available to GIW’s staff and provides them with a ‘best practice’ modelling strategy for similar components in the future.
The models of the pump casing, which is cast in two halves, were then used to produce conventional patterns for GIW, using Cti’s large scale 3 axis CNC machine. This demonstrated the accuracy and speed of manufacture possible when using CNC technology.
Pete Bond also modelled the impeller which is not a straightforward task. The blade, or vane, surface shape is critical for the most efficient functioning of the component and the modeller must take care to get the surface to blend smoothly and accurately.
The pattern was part machined using the model and part hand crafted. A master was made for the vane, allowing resin duplicates to be made quickly and efficiently.
All three patterns were shipped to Georgia for moulding and casting, the impeller in high chrome white iron and the casing in ductile iron.
In a further collaborative project, GIW also made use of Cti’s sand machining facilities to evaluate the advantages of the Patternless® process for their products. The 3D models, produced for the conventional pattern equipment for the hub and suction halves of the pump casing, were converted to provide the data for the direct machining of the sand moulds.
The mould envelope of 1660 x 1520 x 940 mm was machined into a silica sand mould, bonded with alkaline phenolic binder. The machined sand surface was coated with a graphite based coating.
The 1000kg ductile iron casting was filled and fed using conventional gating and risering techniques. The casting is shown in the photograph, prior to shipping.
The machining time for the mould was 6 hours. Cti’s recent purchase of a reconditioned 20 tonnes/hour continuous mixer will facilitate the preparation of sand blocks up to a size of 3 x 3 x 1.5m.