Project Dashboard Heat Beds Heat Beds-Mini Workflow

1 Prep PEI

First we will prep the PEI to be attached to the borosilicate glass bed. Open a precut package of PEI sheets for Mini and attach to the oven rack via binder clips (see picture). These need to be hung so that the natural curvature of the PEI allows heat to rise to the top of the oven for an even bake (see images). Once the oven rack is full we will bake the PEI for a set amount of time depending on weather conditions. Check the humidity to determine the bake time.

Humidity:

0%-69% - 1 hour and 30 minutes

70%-85% - 1 hour and 45 minutes

85%-100% - 2 hours max

NOTE: Do not exceed 2 hours when baking the PEI it can cause the adhesive to run and create bare patches lacking adhesive, as well as introduce microbubbles that will cause "silvering" during post bake

Precut Mini PEI sheets
Hanging PEI on Oven Rack. (this shows TAZ PEI but the process is the same)
PEI hanging in oven so that the curvature allows heat to rise to the top of the oven (this shows TAZ PEI but the process is the same)

2 Prep Glass

Once the PEI has finished baking we are ready to apply it to a borosilicate glass bed. To start we will inspect the glass bed for chips and trapped air bubbles (see images). Do not use glass with trapped air bubbles. Some minor chips can be cleaned up with a glass file, but if they are too bad do not use the glass. Now we will spray the glass with some AP115 Silane Glass Treatment. This allows the adhesive to flow/spread across the surface of the glass for optimal adhesion. Use 3-4 squirts covering the entire surface area of the glass and wipe til dry with a clean paper towel.

Chip in corner of glass
Trapped air bubble in glass
AP115 Silane Glass Treatment
Wipe the glass clean after applying the Silane Glass Treatment

3 Apply PEI

Now that the borosilicate glass is prepped we are ready to apply the PEI sheet to the glass. First grab a sheet of baked PEI from the oven and do an initial inspection of the PEI. Look for small microbubbles or patches that no longer have adhesive. If you find some PEI with patches of adhesive missing, you may be able to still use some of the PEI on a mini heat bed, avoiding the missing patch of adhesive. Do not use if there are microbubbles present throughout the sheet or the PEI will "silver" in post bake.

Now we will attach the PEI to the glass. Pull the adhesive backing about halfway off the PEI sheet. Attach the PEI to the edge of the glass with the PEI sticking nearly straight up, about 90 degrees from the surface of the glass (see images). Next, feed the glass with the PEI attached to the edge into the roller to ensure no air bubbles are trapped during the lamination process. Keep the PEI at about a 45 degree angle to the glass when feeding through the rollers and peel the backing as the roller pulls the glass and PEI through (see images). Try and keep the backing on as long as possible. Dont peel too much because if the PEI falls and touches the glass you will end up with trapped bubbles. Feed all the way through the laminator and you will have a piece of glass with PEI attached and no trapped air bubbles.

Now we need to trim the excess PEI off the glass bed. Using the adjustable razor blade and cutting mat, push two blade sections out of the razor to allow enough clearance from the edge of the glass to trim the PEI (see picture). Run the blade along the edge of the glass just enough to "score" the PEI. Now fold the edge of the PEI forward and it will snap free (see picture) and you can remove the trimmed edge (see picture).

Adhesive backing peeled about halfway off the PEI sheet
Attaching the edge of the PEI to the glass with the PEI about 90 degrees from the surface of the glass
Feed the glass with PEI attached to the edge into the roller to ensure no air bubbles are trapped during the lamination process
Peel the backing off as the laminator pulls the glass and PEI through the rollers
Keep the backing on as long as possible to avoid trapping bubbles.
PEI applied to borosilicate glass bed
Run the razorblade along the edge of the glass on all 4 sides
Fold the PEI forward and it will snap free.
PEI edges trimmed to be flush with glass

4 Apply Heat Pad

Now it is time to attach the silicon heater pad to the back of the glass and PEI assembly. Clean the backside (glass side) of the PEI and glass assembly with a little acetone and wipe clean using a clean paper towel. Inspect the backside of the heat pad for dented corners and creases. Also peel the majority of the adhesive backing off and inspect the adhesive side for bubbly adhesive, debris, and creases or missing adhesive patches.

Before applying the heat pad, crease the adhesive backing diagonally (see image). Attach the first corner and check the alignment on your second corner. If the alignment looks good on your second corner check the remaining two corners dont overhang. Once youve checked the alignment of all four corners press near the diagonal crease with two fingers to get the adhesive started (see image). Now working from the first corner use the hand roller to apply firm pressure and work toward the crease. Slowly peel the backing while using the hand roller to ensure you dont trap air bubbles. Once the backing is off and you have rolled the pad on, run the roller around the section where the wires go into the pad. Use your finger to push any remaining bubbles down.

We are now ready for the second press. Raise the top roller and put the heat bed in between the rollers, use the hand wheel to adjust the pressure. Crank the hand wheel to 60%pressure.

Now, feed the Mini bed through the laminator PEI side down on the butchers paper (see images) l. Run this all the way through the laminator making sure the connectors arent going to be crushed by the rollers (see images). Once this has gone all the way through the rollers the second press is complete.

PEI and glass assembly ready for silicon heater pad
Clean backside with a bit of acetone
Inspect the heat pad for bubbly adhesive, debris, and creases or missing adhesive patches
Crease the adhesive backing diagonally
attach the first corner
line up the second corner
after lining up the first two corners and checking the alignment of the last two, attach two contact points with your fingers
Use the hand roller to start attaching the heat pad. work toward the diagonal crease
Use the hand roller to start attaching the heat pad. work toward the diagonal crease
Slowly peel the backing while using the hand roller to ensure you dont trap air bubbles
Run the roller around the raised section where the wires go into the pad
Use your fingers to try and push any bubbles down
60% Pressure on laminator
Place on Laminator PEI side down on the butchers paper
feed through laminator
ensure the connectors wont get crushed when running through laminator
Second press complete

5 Post Bake

Now that the second press is complete it is time to run the bed through the post bake cycle. Fill the rack in the post bake oven as pictured.

Run the post bake cycle for 1 hour and the post bake will be complete

Oven filled, ready for post bake.

6 Hot press

After the post bake, while the bed is still hot, put it through the laminator rollers again the same as in step 4.

7 Tester

After post bake it is time to run the beds on the tester. There are two different sd cards one has a 30 min cycle and the other is a 50 min cycle. If the bed has been sitting for 2 days or longer use the 50 min test. If the bed has been sitting for less than two days use the 30 min cycle. After the test is complete inspect the beds for bubbling or silvering. If the bed passes the tester, it is ready for use in the production line or to send to the store.

beds on the tester (this shows TAZ beds on tester but the process is the same)
Done! Take me home