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Nov 7, 2011

VERO Software helps deliver a new collapsible snow shovel, designed to help motorists avoid getting stranded this winter

With its two-hinged handle, the collapsible shovel is designed and manufactured by plastic moulding experts Senior and Dickson with the help of specialist CADCAM tools from Vero Software.

While the snow shovel is primarily aimed at motorists because of its handy folding design, the manufacturers also expect it to become an essential tool for helping householders keep their driveways clear of snow and other debris with its unique interchangeable shovel and fork heads.

Senior and Dickson are specialists in plastic injection, rubber moulding and die casting. By linking their experience of injection moulding, tool making and rapid prototyping, they readily develop ideas from concept through to working prototypes and on to production tooling – as demonstrated by the snow shovel project.

The VISI suite of CADCAM software was instrumental in designing the head configurations, specialist handle and 3D tooling, along with the CNC toolpaths. All design work and electrode extraction is performed in the CAD office while toolpath generation is carried out on the shopfloor next to the milling machines.

Chris Hodgson, Technical Director, explains the advantages of taking the toolpath creation out of the CAD office. "We moved the CAM onto the shopfloor as the machinists are closest to the action and can react immediately without having to wait for the design team. They know what tooling is available and how to best machine an insert or electrode." The electrodes are extracted directly from the 3D inserts by the CAD office and passed to the shopfloor for manufacture. The graphite electrodes are machined using Hurco Ultimax VMX50 machining centres (50"x26"x24" machining envelope) and then sparked into the tooling using an Agietron 3U cavity sinking EDM machine.

VISI Modelling was key in both designing the original handle and then strengthening it by allowing Senior Design Engineer Karl Freeman to add further ribbing to the existing model and easily apply the changes to the tooling inserts. Based around the industry standard Parasolid kernel, VISI provides complete flexibility to construct, edit, deform and repair complex 3D data. Chris Hodgson says after trialling the first prototype they chose to add cross ribbing to the shaft to give it greater sideways strength and apply larger radii to remove a localised stress point which caused part failure during stress testing. “This was very easy to do in VISI because the software is not constrained by rules or a previous design history. You can simply jump back into the design process any point – you’re never stuck with a model that you can’t alter.”

Once the model had been finalised, the 3D tooling was designed using VISI Mould and then manufactured from P20 pre-treated steel for the shovel head, and H13 hardened steel for the handle and hinge. The shovel handle and folding mechanism are produced using a high performance polycarbonate and the shovel head is produced using a recycled polypropylene which is commonly used and resistant to fatigue.

The shovel concept began with a wooden handle, but Senior & Dickson quickly realised that this was impossible because of the angle required for it to connect to the head, and turned to VISI to design the model for a moulded handle. “We looked at using a cranked handle, and followed on from that with a folding design to make it much more convenient to store. At around two kilos the shovel is extremely lightweight, and with the folding handle it fits inside the smallest postage bag, keeping post and packaging delivery costs down for online customers.”

When full production is up and running, the shovel is likely to be available though many High Street stores and eventually through DIY/Home Improvement sheds.

Focussing on the relationship with Vero, Chris Hodgson says before switching to VISI from another high end software system, it often took 2 or 3 weeks to produce tooling, but VISI has reduced that time to just three or four days. A fact echoed by Karl Freeman, who also points out that VISI’s speed and ease of use means the design office is now producing more high quality work with fewer members of staff.

Both agree that Senior & Dickson would not be as successful without using VISI, which they say gives them a competitive edge. The company has been in business since 1981 and provides an extensive service of design and manufacture to a number of major clients that includes Hotpoint, Spear and Jackson and Stewart Golf. “We do not specialise in any one particular area,” comments Chris Hodgson. “But thanks to VISI, we master them all.”