Do you have problems removing large parts off of your 3D printer?
Do you have to replace the PET tape on the glass Bed every couple of prints?
I have noticed that when I build large parts I find it very difficult to lift the part off of the bed. The part sticks so strongly that I sometimes damage the part just by removing it.
There are a couple of things you need to do when you want to make a part on your 3D printer. This list is the standard procedure for printing on the TAZ series.
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- Add PET tape to the glass bed so you do not damage the glass.
- Add Lulz juice to the PET tape. This ABS solution provides a layer of ABS plastic which the filament will adhere too.
- Level the bed. You must level your printer bed in between every couple of prints.
Doing this procedure I have found a number of issues with the quality of the bed and the parts I am printing.
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- The part sticks incredibly well to the PET tape. So much so that I often damage the tape attempting to peel off the part.
- When I remove the part the Lulz juice is also removed with the part. This leaves an uneven surface of the bed where there is no ABS material where the part used to be and ABS material over the remainder of the surface. This requires a new layer to be places of the PET tap, which then causes the Abs layer to build up.
- Each sheet of PET tape will allow me to print between 1 and 8 parts. After this time the tape is either damaged by a knife while I am removing the part or the ABS material builds up so much that the surface is unusable.
The Root Cause
I have noticed that these issues result because of the size of the parts I am printing and the amount of effort that is required to lift the part off of the bed. Any part that is greater than 10 mm X 10 mm on the build plate tends to have a very high surface area and therefore a very high surface tension. The part sticks to the surface more, requiring more force to remove. By reducing the surface tension the part will peel off easier and cause less damage.
The Solution - the “Spineless Brim”
SPINELESS BRIM- An array of tiny rectangles added to the bed side of the part. This allows the part to be removed easily.
The solution requires you to add a brim to the part itself. I created the Brim on the part using my CAD software. CIRA is not able to make this custom Brim. There is a brim feature in Cira but it does not do what I need. This brim will consist of small squares, rectangles or circles spaced evenly apart with a very small height. In the photo I have used an array or rectangles. Each rectangle is 4 mm X 1 mm x 0.4mm (W x L x H). Each rectangle is spaced 1mm so the part rests on an array of little stands.
This array lowers the surface tension between the bed and the part. When you lift the part off you are separating a number of smaller parts instead of attempting to peel off one big part.
The Benefits
There are a number of benefits to this technique.
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- The part come off very easily off of the bed.
- The part has a lower chance of being damaged when it is being separated from the bed.
- The PET tape does not get damaged. The brim raises the part a fraction of a millimeter off of the bed allowing enough room for a knife edge to get under the part without cutting the PET tape.
- When you remove the part the ABS layer created by the Lulz juice is often not damaged. What is left is an image of the brim. You do not need to add Lulz juice between prints. The surface can last longer before it needs to be replaced.
I have used this technique for smaller parts as well and the result are very helpful. The only thing you might want to be aware of is that the brim adds a textured surface to the side of the part. The brim has a height of 0.4mm but the textured surface on the part is not that high. Most of the brim stays on the bed. The textured surface is only noticeable when you rub it with our hand (less than 0.1mm).
I hope this helps you make better parts.
Chris Pinter (aka Spineless)
