Vacuum Forming

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Vacuum Forming Station

Introduction[edit | edit source]

Industry Uses[edit | edit source]

Vacuum forming technology is a low cost and a highly efficient tool used to replicate, scale, or prototype any desired shapes using a range of materials. The HD 2424 Vacuum Former Starter Kit implements a magnetic lock system to secure and pressurize air within the chamber, allowing the thermoplastic sheet material to stretch and form to a mold and create a part. Being an alternative for 3D printing, vacuum forming has an advantage against complex edges and saves time by forming multiple units in a short process.

Many vacuum forming processes include: dental, aerospace, special effects, military, Holster Making, Knife Sheath Forming, Hobbyists, Cosplay, Costume Makers, Orthotics, small prototyping and many other types of thermoforming.[1]

Vacuum Forming Machines Available[edit | edit source]

The available mechanical engineering vacuum former is located in the Rapid Prototyping Lab (Room 125) inside the Gauss Johnson Engineering Lab. The sign up process to use these machines is based on a first come first serve basis. For more information on how to use these machines find a graduate student and/or go to the IEW office (GJ 113).

HD 2424 Vacuum Former - Starter Kit[edit | edit source]

Labeled Vacuum Former Parts

1) HD Press 2424

2) High Temp Heavy Duty Membrane

3) Neodymium Magnets

4) Heatsink board

5) Premium Quality Liquid Filled Vacuum Gauge

6) ON-OFF Valve

7) Vacuum Release Vent

ON/OFF positions of Vacuum Valve

Thermoplastics for Vacuum Forming Applications[edit | edit source]

  • Kydex

Kydex Thermoform Plastic Sheets are a line of thermoplastic acrylic-polyvinyl chloride materials. For some applications it is used as replacement for leather, where it has the following advantages: waterproof, scratch resistant, holds its shape better, and will not stretch or shrink under normal conditions lower friction.

Applications: Aircraft Bulkhead Partitions, Firearm Holsters, Sheaths, and for Knives.
  • Boltaron

Boltaron is a proprietary, fire retardant, extruded thermoplastic alloy offering extreme durability, chemical resistance, and a UL 94 V-0 rating while exhibiting exceptional physical properties.

Applications: Firearm Holsters, Medical Device Enclosures, Electronic Equipment Housings, Kiosk Housings, Store Fixtures and Displays Kennel Housings
  • ABS

Because ABS Thermoform Plastic Sheets is low cost and has superior physical properties, ABS (Acrylonitrile-Butadine-Styrene) is one of the most popular thermoform plastics used for vacuum forming. ABS produces detailed parts that are tougher and more rigid than other plastics. It is manufactured in both black and white with a “haircell” texture on one side that helps resist and hide scratches, making ABS a popular choice for parts that need to stand up to heavy use.

Applications: Prototypes and Production Parts, Plaster and Concrete Molds, Drone Parts, Theater Props, Cosplay
  • HIPS

High Impact Styrene is an inexpensive thermoform plastic that is easy to work with and produces excellent vacuum forming results, making styrene the perfect "beginner plastic" for folks who are new to vacuum forming. High Impact Styrene is capable of reproducing intricate mold details along with complex part geometries. It is smooth on both sides, comes in opaque white, and readily accepts paint.

Applications: Prototypes, Packaging, Soap and Candle Molds, Scale Models, Theater Props, Cosplay
  • PETG

PETG Thermoform Plastic Sheets (Polyethylene terephthalate) are a transparent thermoform plastic that offers cost-effective vacuum formed parts with deep draws and precise details. PETG is significantly less prone to cracking than acrylic (Plexiglas). It is used for vacuum forming all kinds of clear plastic parts - especially blister and clamshell packaging and point-of-purchase retail displays. PETG is also FDA food safe and is commonly used to make molds and other kitchen products.

Applications: Blister and Clamshell Packaging, Candy and Chocolate Molds, Theater Props, Cosplay 
  • Wonderflex

Wonderflex Sheets look like a piece of plastic, but it becomes soft and malleable when heated. It can be shaped by hand or over a mold while hot. Once it cools down it hardens retaining the shape. It can be re-heated and reshaped as many times as necessary, or worked in sections. It glues to itself if enough pressure is applied. It can be cut with scissors and finished with paint, gluing fabric on top, or any other method. It can be heated with a heat gun, a microwave oven, or dipped in hot water.

Applications: Theater Props, Cosplay
  • Worbla

Worbla Sheets use hot air, water or steam (min.90 degrees C) to shape the plastic however you want. The material is heat-formable and solvent-free. Scraps can be conditioned and 100% re-blended, so there is almost no waste. These leftovers can be molded just like putty.

Applications: Theater Props, Cosplay
  • Polycarbonate / Lexan Thermoform Plastic Sheets

Polycarbonate (often sold under the trade name "Lexan") is the virtually unbreakable thermoform plastic used to make bulletproof glass. Thin-gauge, transparent Polycarbonate is the material of choice for folks who build ultra light, thin plastic parts that are exposed to a lot of abuse.

Applications: Prototypes, RC Car Bodies, Slot Car Bodies, Model Airplane Parts, Drone Bodies, Drone Parts
  • Styrene
  • Cork
  • Leather

Vacuum Forming Video Help[edit | edit source]

Set-up / Procedure[edit | edit source]

Heat Press[edit | edit source]

Heat press and teflon sheets

1. Before beginning, the user of the heat press MUST be wearing the provided heat resistant gloves throughout the whole process of heat pressing.

2. Place and align the product to best fit, as well as any provided Teflon sheets onto the press to avoid material residue.

3. Plug in the power supply for the heat press and turn the switch on. The switch will be found on the left side of the heat press.

4. Once the press is turned on, let the machine pre-heat to its set temperature.

5. On the front panel, the two settings for TEMP and TIME must be adjusted to the user's preference. Look up the correct temperature in the table below.

  • To adjust the temperature, press the TEMP button once and use the up or down keys to either raise or lower the heat. Once selecting the temperature, press the TEMP button once again to confirm.
  • To adjust the time in seconds, press the TIME button once and use the up or down keys to either raise or lower the time to heat. Once selecting the time, press the TIME button once again to confirm.
Temperature scale for different plastics

6. Lower the press onto the material while pushing down to lock and secure the press.

7. When the machine timer sounds on at zero seconds, gently lift the press.

8. Power off the machine and remove your finished product from the heat press while cleaning and disposing any left over material around the station.

Vacuum Former[edit | edit source]

Before operating the vacuum former, ensure the high temperature membrane is installed correctly for a complete product to work. While placed on the former, the corners of the membrane must be aligned and secured by the magnetic system. Each magnet should sit well within their designated slots to seal the air to create a product.

Magnetic system to lock and secure air

To operate the vacuum former:

1. Place the product mold in the center of the heat sink board to allow an even surface area between the sealed air and the thermoplastic sheet material.

  • Make sure part and hole(s) in heat sink (shown below) are aligned properly to allow for adequate air removal by the vacuum pump.

Heat sink with pre-drilled holes

2. While closing the former, hold down the lid to seal away any excess air and continue to press down until the forming process is complete.

3. To begin vacuum forming a product, turn the valve to the OPEN position and power on the pump. The power switch of the pump is located on the back end of the handle, near the power adapter. (The valve should be sealed or aligned vertically before operating the vacuum former).

Off and on switch on the pump

4. Once the pump has removed all the air from the work area and has been fully pressurized to around -26 inHg, turn the valve to the CLOSED position and power off the pump. Allow material to cool before releasing pressure.

Closed Valve Aligned Vertically

5. (OPTIONAL) To cool off your vacuum formed part faster, use the provided spray bottle to spray small amounts of cool water onto your part which is under the membrane. Then use the provided paper towels to dry the water off. The membrane is completely water proof so there is no risk of damaging it, but be weary of any water getting into the air pump as this could damage it. Always dry off any water with the paper towels. If the spray bottle is empty, refill it and replace the bottle on the storage shelf.

6. Finally, free the air by pushing and holding down the release found on the right side of the vacuum forming machine. Open the lid and remove the finished product and any left over material at the station.

Button to release air

7. After your vacuum forming is complete, clean the membrane with the spray bottle and paper towels or a sponge. This will ensure a tight vacuum seal for the next user.

  • To clean: Run a damp paper towel over the entire membrane surface on the side that will contact the work area. Pay particular attention to the region on the membrane that touches the sealing edge on the vacuum former base. You do not need to remove the membrane from the vacuum press to do this. This only takes a few seconds to do. Again, be sure to dry off any water from the membrane to ensure that no water gets into the vacuum pump system.

Troubleshooting[edit | edit source]

Clean Membrane[edit | edit source]

The most common reason for the HD vacuum former to lose vacuum is a dirty membrane. Any dust/debris accumulation on the HD vacuum forming membrane may cause the press to slowly lose vacuum. The membrane itself creates the seal with the unique design of the HD Vacuum Press, so it is important to pay close attention to this.

Edge Allowance's[edit | edit source]

Before moving on to further troubleshooting steps, double check that your molds are not too close to the outside edge of the heatsink. Modify your molds to provide enough work area around them for the membrane to engage the sealing edge or upgrade to a larger press size if your molds cannot be modified to fit properly.

Use the Heat-sink[edit | edit source]

The Heatsink Board is an important part of the HD Vacuum Press. To get the best seal possible in your HD Vacuum Press it is vital that you use the heatsink board as a work platform.

Check Internal Plumbing[edit | edit source]

To check the plumbing underneath the HD Press:

Remove heatsink and switch your vacuum pump on. Open the control valve and plug the vacuum port(s) in the center of the vacuum grid with a wetted thumb. When you have a good seal with your thumb, allow vacuum to build to its highest point, close the control valve, and check the vacuum gauge. Vacuum gauge should not move until you remove your finger. It should hold full vacuum if there are no leaks in the plumbing and fittings attached to the press.

Obtain Best Seal[edit | edit source]

In order for the HD Vacuum Press to hold vacuum pressure without leakage, it must first achieve maximum InHG to seal properly.

First, ensure that you are using a fast enough vacuum pump (3CFM or higher - see below) to fully evacuate all air from the vacuum press. With the heatsink in place, allow your vacuum pump to fully remove all air from the press and reach approximately 25 InHg or higher on the vacuum press gauge (relative to your elevation above sea level - see below) before closing the vacuum control valve and shutting off your pump. Your vacuum former should now hold vacuum as expected.

Post Form Processing[edit | edit source]

Mold Removal[edit | edit source]

It is crucial to ensure the pump is fully powered off before releasing the pressurized air. With the valve in the CLOSED position and pump completely off, allow to cool and release the pressurized air by pushing down on the black button found on the right side face of the machine. The air pressure gauge should release from around -26 inHg to 0 inHg.

Pressure gauge inHg

Clean-Up[edit | edit source]

Turn off all machines, clear any leftover materials and return them to their original locations.

Rules and Policies[edit | edit source]

Protective Wear[edit | edit source]

Users must wear provided gloves when removing hot material from heat press to avoid being burned.

Vacuum Forming Policy[edit | edit source]

The Mechanical Engineering Department maintains the vacuum former for sole use by faculty, staff, and students. The use of the vacuum former shall be consistent with the purpose of the department, which includes facilitating research and learning. In accordance with these purposes, the department has developed policy and procedures for use of the vacuum former:

1. Administration. All projects (i.e. components) to be formed shall require permission from a faculty member. All projects must originate from U of I classroom, lab, or research. To clarify, personal projects are prohibited.

2. Prohibited Uses. Regardless of viewpoint, certain uses of the former are prohibited and violate this policy:

(a) Forming any object that is unlawful, threatening, abusive, tortuous, obscene, or unethical is prohibited.

(b) Forming any object that is intended to physically harm, or attempt to harm, an animal or person in any way is prohibited. This includes weapons (i.e. knives, firearms, etc.) or parts of a weapon (i.e. blades, gun triggers, etc.)

(c) Forming any object that infringes upon a patent, trademark, trade secret, or copyrighted material without consent is prohibited. The department reserves the right to deny use of the vacuum former's if, in its judgement, use of the former's would violate Copyright Law.

(d) Vacuum forming any object or any part of an object that is government regulated. For example: Undetectable Firearms Act of 1998 which specifically bans plastic firearms.

3. Usage Subject to Refusal or Revocation. The vacuum former is provided to further the purposes of the department. In accordance with this policy, the department may refuse usage of the vacuum former at any time. Failure to abide by this policy may result in revocation of the user’s forming privileges.

References[edit | edit source]