True to form

27 June 2012

A vacuum forming company dramatically trims cycle times using five-axis machining software

Leeds-based Vacform Group is a vacuum forming company supplying a wide variety of products to diverse industries from aerospace and automotive through to education and entertainment.

Technical director Mustafa El-Etriby driving VISI Machining five-axis

With vacuum formed products becoming increasingly complex, three years ago the company decided to invest in VISI Machining five-axis software. “Without the five-axis capability that VISI Machining, from Vero Software, gives us, we just wouldn’t be able to compete in the market,” says Vacform Group’s technical director, Mustafa El-Etriby.

El-Etriby currently undertakes all programming for the company’s five axis Geiss ECO trimming machines himself, and is impressed with the complete control the software provides over the five-axis toolpath, the tilting of the tool axis, the lead-in/lead-out methods and toolpath editing capabilities needed for vacuum formed components.

“It is by far the most efficient way of getting the job done. We can even program quite complex parts in just 15 minutes,” he comments.

While trimming off the scrap to give a perfect, clean finish, VISI also controls the perimeter cuts and hole features. The cut is achieved on the side of the tool, with tilt lines being one method used to drive the head around a given surface.

Collision avoidance

In addition to the accuracy of toolpaths and the added efficiency that VISI Machining five-axis gives to its shopfloor operation, managing director Kevin Quinn highlights another vital aspect: “We use the powerful kinematic simulator to make sure the toolpath is collision-free.”

“If you bang the head on the machine it can cost £2,000 to recalibrate it, so every program is verified on the kinematic simulation which has been an absolute godsend for our programming. It walks us through the complete program and shows where any problem will occur. We then go to each tilt line and tweak the toolpath to get it right based on how we need to manufacture the part,” he explains.

VISI’s collision avoidance strategies include cutter retraction along the tool axis, tool tilting for holder collisions and pulling the tool away from the work piece in a given direction. As well as the full automatic collision avoidance, the rotation axis can also be restricted to user-defined axis limits.

The full process

The full production process starts when Vacform Group receive customer drawings in a variety of CAD files, or its in-house design team uses SolidWorks to design the moulds, which are then machined predominantly from aluminium or fibre board on a three-axis Bridgeport machine. Once the product has been vacuum formed, trimming it on five-axes provides the accuracy, efficiency and control that the company would not be able to achieve otherwise.

“We take the vac-formed part, put it on a CNC jig, and VISI finishes the component. It takes all the labour and human error out of it. Also, it’s just one process for trimming. If we did it manually, not on five-axes, we would need up to six separate processes to trim certain parts,” says El-Etriby.

While Vacform Group strives for perfection every time, there are certain variables beyond any control, such as the thickness of the material, expansion and contraction tolerances on the tool, and the temperature. “But VISI’s five-axis capability means we have better control over tolerances normally associated with more expensive injection moulding. We can build strengthening ribs in as a feature by creating radii.

For some customers we work to a tolerance of 0.1mm on the trimming, which we just couldn’t achieve without five-axis,” adds El-Etriby. So, VISI Machining has certainly been a worthwhile investment.
“The enquiries we’re currently getting relate to very complex parts, and I just can’t see how companies can produce good quality vacuum formed parts without five-axis offline programming. VISI has certainly brought us into the 21st Century over the last three years. Our Geiss machines are now used to maximum capacity and we have cut downtime by at least 40 per cent,” concludes El-Etriby.

www.vac-form.com
www.vero-software.com

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