The VISI suite of CADCAM applications from Vero Software has been instrumental in helping a precision engineering company develop the world’s most advanced commercially available myoelectric prosthetic hand currently on the market.
Delta Tooling (Horsham) Ltd was approached some two years ago by prosthetics specialists RSLSteeper to assist in the manufacture of the bebionic3 prosthetic hand, which is transforming the lives of amputees worldwide, helping them to regain independence and control in their everyday lives.The bebionic3 utilises leading-edge technology to trigger one of 14 programmed grips, perfectly mirroring human movements. Being the culmination of many years of work from RSLSteeper, the bebionic3 hand is designed so that its unrivalled versatility, functionality and performance allows its users to carry out everyday tasks such as using a computer keyboard, tying shoelaces and chopping vegetables.
Operating from Billingshurst in West Sussex, Delta Tooling now manufacture five parts for the hand, including the aluminium knuckle, the plastic sub-section it connects to and a complex thumb bracket that allows the opposable thumb to rotate and move backwards and forwards. RSLSteeper originally approached Delta Tooling’s directors Gary Childs and Luke Tetlow with an all-plastic moulded product which had to be partly machined when removed from the mould tool. “The initial concept of casting or moulding the components, followed by finish machining operations before assembly and testing, gradually evolved into fully machined parts to improve quality and maintain consistency,” says Gary Childs. “Maximising our use of VISI Machining, we developed strategies that not only machined the parts from solid billets, but produced them in highly competitive times.”
The initial 3 + 2 machining was carried out on Delta Tooling’s range of DMGs and Bridgeports, which were programmed extremely effectively with VISI. However, as the complexity of the components grew, it became clear Delta required the flexibility of full continuous 5-axis machining. “We invested in an AgieCharmilles Mikron UCP 800 Duro and updated our machining software to the latest 5-axis release of VISI 20. This not only gives a better quality finish on the product but means we can manufacture it in a more efficient timescale, thereby reducing the number of set-ups and producing cost effective production runs.”
5-axis machining is perfect for manufacturing the bebionic3 products, and VISI provides Delta Tooling’s operators with a productive solution for preparing the geometry for manufacture and creating the highly efficient toolpaths required to manage the increasing complexity of the components involved. CAD data is readily imported into VISI in whatever format the customer supplies it, whether it’s a STEP, IGES or Parasolid file. “We carry out various checks on the file to ensure its integrity, before laying it out in a way that can produce the component from the machine tool’s point of view. Then we’ll assess the part’s machineability.”
As part of that process Delta Tooling find VISI Machining’s collision control and kinematic simulation extremely valuable. “Having made a major investment in a new 5-axis machine, the last thing we want is to cause a collision. We always run full kinematic simulation prior to any production run.” A new feature in VISI 20 which Gary Childs says represents “a huge step forward” for them is the dynamic incremental stock (DIS) command that automatically creates the stock model from the uncut material of previous toolpaths, to be used as reference data for subsequent milling operations.
It automatically trims the toolpath to remove unnecessary movements and fresh air cuts. “This allows us to machine rough from one side of the component. When we turn it over we have a new machining cycle that allows us to rough again, but we’re not cutting fresh air. This reduces machine cycle time further, making us even more efficient.”
Having their roots in mould and press tool making, Delta diversified into producing fully machined parts, honing their skills with critical components for a number of F1 sector and wave guide components for space satellites. “The combination of our 5-axis machines and fully integrated VISI CAD/CAM package means we can react extremely quickly to our customers’ demands – especially the motorsport industry,” says Gary Childs. “For this reason, it is imperative that the VISI support team are able to react equally as quickly and they have never let us down. It’s clear they understand our industry and our manufacturing needs.”
The Mikron runs almost constantly across two shifts from 8 a.m. to 2 a.m. the following morning, manufacturing to a call-off order for RSLSteeper on a monthly basis, as well as machining components in additional production runs for Delta Tooling’s motorsport customers. “We’ve built a solid reputation based on our speciality of producing complex parts with a very quick turnaround time, and a number of customers have been with us for several years. VISI has already helped us make our mark as a company in the 3-axis market place and now the combination of the new 5-axis Mikron machine tool and VISI 5-axis Machining is making us even more efficient and very competitive.”
The bebionic3 was unveiled worldwide in the United States in September, and subsequently introduced to the United Kingdom at a London launch in November. It looks as if RSLSteeper’s design innovation along with VISI and Delta Tooling’s expertise will ensure the product’s future progression and manufacturing for a long time to come, maintaining RSLSteeper’s vision of improving amputees’ lives.