Is the Heat bed tape needed?

glyn Wrote:
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> What is special about mirror glass?

To get a good reflection the glass is very flat. Similar goes for window glass. Can be cut to size, but may also crack if stressed by uneven heat.

Any other glass for shelves, mats or whatever don't need good optical properties. These are usually tempered glass which withstand uneven heat well but which shatter if you try to cut or drill it.

Bitdude Wrote:
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>
> I just tried pet sheet I ordered with mendelmax
> parts from store.mendelmax.com and it is just as
> hard to remove the parts from it as the kapton
> tape. It does go down easier being one sheet as
> opposed to the four stripes of 50mm kapton it
> normally takes. I have however found it almost
> impossible to remove the skirts or other traces of
> abs from it.
>
> I am going to try a fresh one and start with a
> lower bed temp as the goal is for parts to hold
> while printing and pop off after the bed cools
> down like the pla does on the glass.
>
> Bob

Is the surface of the PET sheet rough or smooth? Did you use ABS in acetone to coat the surface? With the 3M tape, I found that parts are almost impossible to remove with the PET tape is sanded and then coaed with ABS/acetone. I print on this PET tape without sanding or coating and it releases parts just like glass when cooled. Black ABS (I think Ultimachine) sometimes need a thin ABS coating so it won't lift while hot.

Parts don't generally pop of when you use tape because the tape has enough give in it to take up the thermal contraction. It is only with solid surfaces with low thermal expansion like glass and FR4 that parts release when cold.

ABS parts come of PET tape easier than Kapton but on the other hand it doesn't have quite as much grip when doing large parts.

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[www.hydraraptor.blogspot.com]

brnrd Wrote:


> Is the surface of the PET sheet rough or smooth?
> Did you use ABS in acetone to coat the surface?

The PET was smooth no surface treatment.. It was a sheet that I applied to the entire print bed.

But there is NEWS to report.

After watching wildeyed on YouTube printing abs on plain glass I decided to give it try with higher heat.
My setup is a Printrbot with custom parts and the mk1 (the print area on the x is almost 9"). I first redid the way the bed attaches so that aluminum strips span the two parallel y bars to which I remounted the print bed with springs to be able to level it better. (yes, I don't like the way the y carraige is on the Printrbot either. That's why I have a mendelmax in construction as dollars permit.) I then procured monster bulldog clips so I could use two layers of cardboard, with aluminum foil as a reflector on the bottom one. (flat silicone sheets on the way). Then mk1 trace side down, thermisistor in middle bottom side. Pyrex on top.

I was able to get it to 115c beating my previous best of 95c. With the glass cleaned and at 115c, the first layer at 120% height and pressed good into the bed, It stuck!!! And I was able to print much like I have with pla and it snaps loose on cooling. No abs juice or anything else. Seems heat and pressure into the print bed does the trick.
( bed at 115c, ultimachine blue 3mm abs, j-head II at 215c, head with 1 paper thickness then both z's rotated 1 half rotation into the bed. First layer at 120%.

Bob

Edited 1 time(s). Last edit at 07/24/2012 08:12AM by Bitdude.

Of course all success must be balanced with some setback. Once I saw the first print underway I left it alone only to discover on my return that I only had half parts!!

I had forgot to reduce the retract rate from pla to the lessor vale for abs and it had chewed the filament at about the halfway point!!

Bob

I have a new reprap prusa i3. The hotbed is made of aluminium, and I also got some kind of tape to cover this aluminium plate when I print PLA, it says.
I also got some kind of plastic plate with small holes in, to use when I print ABS. Am I supposed to print directly on this plastic plate without any tape?

What shall I use when I print nylon? Does it works with the tape?
What happens if I just put a peace of paper on the plate and print on the paper? Will it burn?

Edited 1 time(s). Last edit at 07/28/2016 07:26AM by Henrik Jansson.

Quote

What happens if I just put i peace of paper on the plate and print on the paper? Will it burn?

try it and see,, I used it for soft PLA once ,it stick to anything really but it was terrible job getting off the bed so the paper was used to make it easy but the down side is it leave an ugly finish! "paper fibre embedded in the surface"

the tape on the bed is that golden in colour?, that be Kapton tape and is good with PLA get the first layer right you can get a smooth mirror like finish on the surface,
" plastic plate with small holes" is that buildTak? and yea you just print directly onto it,

No, the tape looks like light-brown-yellow papper. The kind of tape you use when you paint and dont want to get paint on something.

But first, I now have to print with nylon, what should I use on the bed then?

Can something go really wrong if I use the wrong material, or will it just be problem to loosen the object after printing?

When you used paper, did the paper got stuck into the bed or in to the object you were printing?