Plug assist application
Deep draw applications e.g. pockets, where the bottom of the formed pocket is very thin once the material has been pulled down with the vacuum.
Where the formed sheet may distort permanently as the release air blows the formed part off the tool or PMMA (acrylic) can crack as the tool drags the formed part down with the table.
Where tall or closely spaced tools are required.
Plug assist shapes
The shape of the plug will influence the way that the material is pushed into the cavity and its distribution.
Plug assist mounting and positioning
Typically the plug will be in the region of 80% the size of the cavity and will descend 70 – 75% of the depth of the cavity, although this is highly variable. The shape of the plug will vary depending on where you want the material to be the thickest.
Pack plug with spacers so that it is in the centre of the cavity – apply foam tape to the top of the plug and bring down the plug and then secure with screws or bolts once you are happy with the positioning.
Manual Plug assist
These can be quite crude or if the production warrants the effort a more permanent plug assist can be created. This will result in much more consistency.
Auto Plug assist
The automatic plug assist is either controlled using a pneumatic cylinder to raise and lower the plug or with electric servo drive.
Pneumatic plug assists tend to have one speed in each direction. Servo powered plug assists can have multiple staged descent and ascent at various speeds, giving you much more control.