Medical technology Software supplier lends a hand to toolmaker for artificial limb

Editor: Eric Culp

Vero Software said its Visi CAD/CAM suite has been instrumental in helping a precision engineering company develop the world’s most advanced myoelectric prosthetic hand currently on the market.

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The bebionic3 hand is said to utilise leading-edge technology to trigger one of 14 programmed grips and mirror human movements.
The bebionic3 hand is said to utilise leading-edge technology to trigger one of 14 programmed grips and mirror human movements.
(Source: Vero Software)

UK shop 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 can transform the lives of amputees and help them regain independence and control in their everyday lives.

Helping out with daily tasks

The bebionic3 hand is said to utilise leading-edge technology to trigger one of 14 programmed grips and mirror human movements. Being the culmination of many years of work by RSLSteeper, the bebionic3 hand is designed so that its versatility, functionality and performance allow its users to do everyday tasks like use a computer keyboard, tie shoelaces and chop vegetables.

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Operating from Billingshurst in West Sussex, Delta Tooling now produces five parts for the hand, including the aluminium knuckle, the plastic sub-section it connects to and a complex 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 that 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,” Childs said. “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.”

Adding machining prowess

The initial 3 + 2 machining was carried out on Delta Tooling’s range of DMGs and Bridgeports, which were programmed with Visi. However, as the complexity of the components grew, it became clear Delta required the flexibility of continuous 5-axis machining. The shop explained that it invested in an AgieCharmilles Mikron UCP 800 Duro and updated its software to the latest 5-axis release of Visi 20. This is said to provide both a better quality finish and allow the company to manufacture the product in a more efficient timescale to reduce the number of set-ups and create cost-effective production runs.

Five-axis machining is said to be perfect for fashioning these products, and the software offers operators a productive solution for preparing the geometry for manufacture and creating the efficient toolpaths required to manage the oft-increasing complexity of the required components.

Suite stops collisions, too

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,” Childs said. “Then we’ll assess the part’s machineability.” He noted that this is where Delta Tooling finds the software’s collision control and kinematic simulation valuable. “Having made a major investment in a new 5-axis machine, the last thing we want is to cause a collision.”

No cutting fresh air

Childs said one feature that represents “a huge step forward” for the shop is the dynamic incremental stock (DIS) command. It automatically creates the stock model from the uncut material of the previous toolpath, to be used as reference data for subsequent milling operations. It automatically trims the toolpath to remove unnecessary movements and fresh air cuts. He said, “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.”

Quick reactions for success

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 satellites. Childs said the combination of the 5-axis machines and the fully integrated Visi suite means the shop can react quickly to customers demands – even in the motorsport industry” “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. ”

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 motorsport customers.

Childs said the shop has built a solid reputation by producing complex parts with a very quick turnaround time. “Visi has already helped us make our mark as a company in the 3-axis marketplace, 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. RSLSteeper’s design innovation along with Visi and Delta Tooling’s expertise should help to ensure the product’s future in order to maintain RSLSteeper’s vision of improving amputees’ lives.

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