Belovac Vacuum Forming Machine
|Make/Model||Belovac BV E-Class|
|Host Area||Hot Metals|
- 1 Overview
- 2 Vacuum Forming Process
- 3 Safety
- 4 Machine Information
- 5 Materials
- 6 Tips & tricks
- 7 Maintenance and Repairs
- 8 Authorizers
This vacuum forming machine has been donated by SAIC and is currently installed in Hot Metals area. A Danger Committee was formed and the machine is ready for member use pending authorization.
How to Get Authorized
Authorization for this machine is on demand and viral. Please make a request on Slack to see when an Authorized member is available and coordinate an authorization.
Please review the information on this page, in particular the Safety section before meeting.
Please bring your own materials, as there is no guarantee there will be any available. A few sheets of thin 12in x 12in ABS/HIPS would be ideal.
This machine is working but requires maintenance and improvements (see list below).
Vacuum Forming Process
Vacuum Forming, is a type of Thermoforming,which is the process of heating a plastic sheet and stretching it over a mold. As the plastic cools, it hardens, permanently retaining that shape.
This device can handle any thermoformable plastic up to 3/8" thick.
Depending on which platen/frame that is used, the machine can accept 3 sizes of plastic sheets. 12inx12in, 24inx24in and 24inx48in. The usable area in those sheets after being secured in the frames being 9.25inx9.25in, 21inx21in, or 21.5inx45.5in.
The "buck," mould or form, may be any sturdy shape that can tolerate a bit of heat. Wood, MDF, metal, and polyester resin work well. Avoid shapes with hollows underneath because they have a tendency to collapse. Shapes with undercuts, or shapes taller than they are wide, will be very difficult to remove from the formed plastic. Paint, shellac, or epoxy resin can cause the hot plastic to stick.
The oven must be used only for vacuum forming. Please do not attempt to use this machine to dry materials or anything other than its intended purpose.
Other related tools/skills:
- ShopBot Auth - to create molds out of MDF with the CNC.
- Woodshop Auth
- 3D Printer Auth
- to create mold to cast plaster buck
The process consists essentially of inserting a thermoplastic sheet in a cold state into the clamp area, heating it to the desired temperature with the heating elements, and then raising the buck/form/mould from below. The trapped air is evacuated with the assistance of a vacuum system. Once cooled, the platform is lowered to release the formed plastic part from the buck/form/mould.
The following instructions are an initial release of how to run the machine.
Please review Safety section below the Instructions.
Please provide feedback or feel free to make edits.
The Vacuum Former has an oven surface for heating and softening the plastic. It is made of multiple panels (total 6) infrared radiant heating elements, draws a total 80,000 watts (top and bottom), and reaches full operating temperature depending on Active heating time set on the timer.
The most likely source of problems would be for someone to leave the plastic under the heater for way too long and set it on fire. To help avoid this error, we are only using the center top panel for heating. Warning: Ignoring safety protocol is cause for revoking authorization.
Fumes from most plastics are not expected to be significant when the machine is used properly (i.e., nothing is on fire). If fumes do turn out to be a concern, the machine can be retrofitted with a fume hood. Then connected to the existing exhaust duct for the Forge. To improve air quality, turn on the forge exhaust and open the front door by the plasma cutter computer.
Company page: http://www.belovac.com/manual_deep_draw.html
- About Vacuum Forming Process
- Makerbot Post Processing: Vacuum Forming
- Overview of newer model
- Custom Vacuum Box creation
NOTE: Materials are not provided. Member must bring their own materials for use with this machine. Please consult material selection guide to select appropriate plastic sheets for thermoforming.
Example Materials for use with the machine below:
Materials for Buck/Form
These are an example of some materials that can be used for molding. The material needs to be heat resistant. It should also have a flat base for stability on the platform.
- Plaster of Paris
- Vac-Master Resin with Aluminum
- MDF Form ( Shaped by Shopbot CNC or purchased pre-shaped )
- Aluminum/Steel Part
Materials for Forming
Information on safe thermo-formable materials in sheets.
Material Selection Guide - https://www.toolcraft.co.uk/vacuum-forming/advice/vacuum-forming-help-material-selection-guide.htm
- High Impact Polystyrene (HIPS)
- Acrylonitrile Butadiene Styrene (ABS)
Plastics Distributors taken from tk560.com
Order full sheets 4'x8' and cut to desired size with panel saw.
Tips & tricks
Creating an appropriate Buck/Mold
- Part should have a flat base
- No overhangs
- Pay attention to draft angles
- Depending on the thickness of the material, a band saw or box cuter can be used to trim excess flashing from the final part.
How long does it take to heat the plastic sheet?
- This depends on which material and thickness is specified.
How do I know when the plastic is ready to form?
- Generally speaking it is necessary with any new material to establish the correct heating cycle. Plastic is ready to form when it becomes soft and pliable especially nearer to the clamping frame. This is known as glass transition temperature (Tg). Once you have established the time you can set the heater timer for accurate and repeated heating cycles.
Why is the plastic webbing on the mold?
- Material is too hot.
- Insufficient vacuum.
- Excess of material. Use reducing windows.
- Poor mold design.
Why can't I achieve good definition on the finished part?
- Material too cold
- Mold too cold.
- Insufficient vacuum.
- Insufficient vacuum holes in the mold
Why Is the plastic thinning over the mold when formed?
- Sheet cooled whilst forming.
- Mold design with insufficient draft angles.
- Too thin plastic gauge.
- Pre-stretch required.
- Plug assist required.
Why does the plastic bubble and pit when heated?
- Material is Hygroscopic which needs to be pre-dried prior to forming.
- Mold or plastic sheet too dusty
Why does the plastic stick to the mould when I try to release?
- Mold not fixed on baseboard.
- Insufficient draft.
- Mold undercuts.
Maintenance and Repairs
- Get Running - DONE
- Add equipment sticker to machine for wiki info
- Fix platen/frame rubber seals
- Build basic test mold for demos and training. (PS1 Logo or Mask)
- Move vacuum gauge to before the valve, to measures the vacuum the pump is pulling (right now it's after the valve, so doesn't read anything useful)
- Install Additional/Larger Vacuum Tank to the system for more capacity
- More powerful Vacuum Pump
- Temperature Monitoring
- Mount Control Panel Box to machine DONE
- Put on locking casters, or more permanent blocks/skid (machine is very heavy)
- make the platen stationary and the heater roll (complicated)
- Reduce the footprint of the machine (complicated)
|Andrew Camardella||By Request|
How to Become an Authorizer
Get an ok from the area host. Successfully run an authorization supervised by an authorizer.