January 13, 2012 - A vacuum forming company says VISI's 5-axis machining played a key role in turning it into one of the industry’s most innovative and market-leading manufacturers in the UK.
Just three years ago the Leeds-based Vacform Group Ltd were using the ‘teach’ method of driving a stylus around the part to program their Geiss ECO trimming machines. “Where we had big complex jobs this could take up to two days, meaning we were losing all that production time while the machine was down and out of action,” says Managing Director Kevin Quinn.
Then they switched to VISI MACHINING 5-Axis software to create the trimming toolpaths. The first job using the software was for a cosmetics Point Of Sale display which won a top design award. The unusual shaped display comprised eight different vac-formed parts that were CNC machined, then bonded together with inserts on the inside. The completed unit looked like it had a continuous machine finished edge.
“That job could not have been manually taught; it wouldn’t have achieved the high level of finish required and just wouldn’t have looked right. We took it on, knowing that VISI would do exactly what we wanted. As it was our first job on the software, we received excellent support and assistance from the Vero team and we’ve gone on to complete many more successful jobs using a range of thermoplastics, including ABS, high impact Polystyrene, Polycarbonate, Polypropylene and High Density Polyethylene (HDPE).”
As well as shop displays and Point Of Sale, Vacform Group Ltd supplies a wide variety of products to such diverse industries as aerospace, automotive, petrochemical, electronics, engineering, education and entertainment, along with their own Decksaver range of Polycarbonate covers to protect audio equipment in clubs and bars around the world.
With vacuum formed products becoming increasingly more complex, Technical Director Mustafa El-Etriby says CNC trimming is the most important part of their operation. “Without the 5-axis capability that VISI MACHINING, from Vero Software, gives us, we just wouldn’t be able to compete in the market.” He currently undertakes all programming for Vacform Group Ltd’s five axis Geiss ECO trimming machines himself, and is impressed with the complete control the software provides over the 5-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.”
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.
As well as guaranteeing the accuracy of toolpaths ensuring consistency to produce parts exactly as they are on the CAD data every time, and the added efficiency that VISI MACHINING 5-axis gives to their shopfloor operation, Kevin Quinn says there is another vital aspect of the software. “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.”
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, preventing over-travel of the rotary axis or left to retract, unwind the head and approach again once the limits are reached meaning that rotary axis limits no longer become an issue.
The full production process starts when they receive customer drawings in a variety of CAD files, or their in-house design team uses SolidWorks to design the moulds, which are then machined predominantly from aluminium or fibre board on a 3-axis Bridgeport. Once the product has been vacuum formed, trimming it on 5-axes provides the accuracy, efficiency and control that Vacform Group Ltd 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 5-axes, we would need up to six separate processes to trim certain parts.”
While they strive for 100% 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 5-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 5-axis.”
Both agree that Vacform Group Ltd would not be so successful without VISI MACHINING 5-axis. “We wouldn’t be as big as we are. Bringing in VISI three years ago was a key decision,” says Kevin Quinn. “This technology is tremendous for us as a company.”
And Mustafa El-Etriby concludes: “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 5-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%.”