MACHINERY | THERMOFORMING
manufactured at the same time on a UA 100g out of 2mm TPU/ABS sheet. Subsequently, a 2-up punching tool punched the parts out of the sheet material in one stroke in a rimless, dust-free way. Up to 8 cycles per minute can be achieved thanks to a fast and easy sheet change, says Illig.
Above: Tony Harris, a pattern maker at Belgrade, puts the finishing
touches on an aluminium mould to make ABS wheel boxes
Right: Illig produced two parts from TPU/ ABS in a live demonstration at Fakuma
Speedy service WM Thermoforming Machines of Switzerland has delivered an FC 780 E HP Extended Speedmaster Plus vacuum/high pressure forming machine to Ireland-based packaging company Holfeld Plastics. The digital thermoforming machine has maxi- mum tool dimensions of 780 x 570mm and a maximum forming height positive/negative of 130mm. The sheet heating section has both upper and lower heater banks with HTS black infrared ceramic heating elements with independently controlled zones – which saves around 15% in heating energy consumption, says WM. The machine includes a punching press for holes and the space to insert an in-line padding machine made by the UK based company Forming Automation for absorbent or bubble padding. The customer uses the machine to make soft fruits punnets in clear r-APET with or without an internal bubble pad. The punnets are simple and effective with a separate lid, and they are available in different dimensions and volumes, vented or unvented, says WM. Forming is achieved by means of compressed air up 7bars and vacuum, which can be pro- grammed in the required sequence. The forming process can be quickly changed between the upper and lower platen.
Part demonstration At last year’s Fakuma, Illig showcased continuous part production on a UA 100g sheet processing machine with subsequent finishing on a steel rule punch press.
During live demonstrations, a stackable storage shelf and an organiser box for screws were
16 FILM & SHEET EXTRUSION | March 2018
Accurate algorithm Jim Throne, a US-based plastics consultant, told delegates at last year’s Antec conference in the USA about an improved algorithm to determine the energy exchange between heaters and sheet in the thermoforming process. Although heaters are usually multi-segmented,
with each being controllable in order to target ener- gy input to different parts of the sheet, calculating the exact amount of energy transfer can be difficult. Calculating the energy transferred from a single
heater element to a single sheet element – using Stokes’ Theorem – is straightforward, but things become more complicated when dealing with multiple elements, he said. “When the parsed elements become many, the arithmetic becomes tedious at best – and very prone to ‘juggling errors’,” he said. Also, the method cannot account for all energy
interchanges – such as those between a heating element and a part of the sheet that is some distance from it. Throne has previously developed calculations that generate an ‘energy dome’ for equal-sized square heater and sheet elements – but realised it was difficult to apply to ‘real’ situations. Instead, he used a
general mathematical form for energy interchange – where the
sheet element can be placed anywhere
in the x-y plane, and the heater element anywhere in the a-b plane. Using this method, there was no restriction on the relative dimensions of either the heating element or sheet element.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.total-corbion.com �
www.econcore.com �
www.dupont.com �
www.kiefel.com �
www.belgrade-polymer.com �
www.wm-thermoforming.com �
www.illig.de/en
www.filmandsheet.com
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