How To Vacuum Form Plastic

So, vacuum forming is an excellent option for proper molding over hard plastics. Typically, experts use this method for more significant parts that must be solid and impact resistant.  

From the hospital equipment to the car parts, this technique has been used in most types of gear. But the real question is “how to vacuum form plastic” and the requirements to make it happen without any problem. 

To give you a simple answer, it is merely done with the vacuum form machine. Are you feeling confused? Don’t panic, as I will try my best to give you an in-depth explanation of the whole method. 

So, without wasting a minute, let’s look into the topic!

How to Vacuum Form Plastic – Step By Step 

If you have a vacuum form machine and need to mold the plastic, this method might help you. Yet, it’s compulsory to have tools, patience, and safety preparations to get the job done well. 

For your information, molded plastic is being used on TV, radio, freeze, and similar products. So, gather all the tools that are vital and jump to the procedure. 

Necessary Tools

  1. Thermoplastic sheet.
  2. Metal clamping frames.
  3. Spring clips.
  4. Kitchen oven.
  5. Aluminum vacuum platen.
  6. Safety gloves.
  7. Vacuum form machine.

Step-1: Set the Metal Clamping Frame

Start by securing the thermoplastic sheet amidst the metal clamping frame. Be sure to attach the spring clips to help them stay fit nicely.

Step-2: Attach the Spring Clips

Put the metal clamping frame and spring clips onto the vacuum form machine. 

Step-3: Began the Heating Process

Using the kitchen oven, warm the plastic at 100° to 225° C temperature to ensure it turns supple or smooth like butter. 

And if this item is not available in your kitchen, use any heater machine (single or twin) in a 6mm to 10 mm distance. The process might take not more than 15 minutes.

Step-4: Align the Metal Clamping Frame to Hot Plastic

After the temperature has reached, maintain the metal clamping frames in the correct alignment when placing the hot thermoplastic. Use the guides and other plastic on top of the mold if possible. 

Step-5: Wait for Some Seconds

Let it stay like this for 3-5 seconds so that it can place adequately. Otherwise, the thermoplastic will not align with the metal clamping frame.

Step-6: Use Vacuum Pressure (Optional)

If needed, try to use the vacuum pressure in order to place the plastic sheet to the right spot alongside the mold. 

Step-7: Shape the Plastic by Pressing It Hard

Shape it in any way to make the plastic look as you would like by pushing the plastic. 

Step-8: Cool Down the Plastic

Once the mold over plastic is done rightly, cool the plastic for around 2-5 minutes. 

Step-9: Inspect It Deeply

Take that out and see if you have got the expected result. 

A small tip is to maintain a 3° draft angle when pulling out the plastic sheet from the structured mold. Or, you can use silicone spray before placing the hot plastic sheet.

Now, the vacuum form plastic can turn into female or male molds. If the thermoplastic sheet has been placed inside where the outer sizes seem essential, then it is a female mold. 

And, if the thermoplastic sheet is wrapped entirely on the top, then it is a male mold. 

Note: Be sure to check the building and forming process as this is where most people fail to ensure a suitable vacuum form plastic. 

Finishing Operation

After the success of vacuum form plastic, you need to face the final method. This may need some extra tools or not based on the condition of the mold. 

If you need to cut the corners of the mold, it’s suggested to use guillotining, press, or roller cutting. Otherwise, the CNC machine would be an ideal option. To do that, you only need to shape the molded plastic edges. To ensure the exterior and interior are fine.

Then again, drilling is another finishing method that you can try to make a round hole. Mostly, it is not necessary, only for small production. 

Frequently Asked Questions

  1. Can you vacuum form over plastic?

Yes, you can! Most of the time, the vacuum form is used as a food package over plastic stuff. And also, it offers parts that are pretty simple to wash.

  1. What plastic do you use for vacuum forming?

The ABS (Acrylonitrile Butadiene Styrene) acrylic, PMMA (Poly Methyl Methacrylic), and PETG (Polyethylene terephthalate glycol) are some of the plastics that nearly all people use for vacuum forming.  

Other than these, you can form or mold the HIPS (high impact Polystyrene sheeting) and PVC (polyvinyl chloride). 

  1. How thick can you vacuum form?

The best range that is suitable for you to use is the vacuum form that has 0.005” to 0.50” (inch) or 0.0127” to 12.7” (mm) thickness. Yet, that’s not permanently fixed as sometimes it needs to be changed. 

If you are using the prototype for vacuum form, then the 0.0005” to 0.25” (inch) or 0.0127” to 6.35” (mm) thickness would be ideal.  

Wrap Up

I hope you have all the knowledge of how to vacuum form plastic after reading this guide. It is one of the ancient techniques to process plastic material from the 1930s.

And, this method hasn’t been replaced by others due to its cheap cost and fast tooling skill. In fact, injection molding tricks don’t work as great as the vacuum form.

It does need lots of focus and attention to do in the right way, especially when placing the hot thermoplastic on top of the aluminum platen. So, I suggest you wear thickly-made gloves.

The direction might seem confusing when you look into it for the first time. But this will get better if you learn each part and follow the instructions using your brain. And, that’s all for today. See You in The Next Article!

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