Raft hard to remove?

Question

I've been having a hard time lately getting the raft off of my ABS prints.

Is that a symptom of either a nozzle or bed that are too hot? Or is there some other factor I should be looking in to?

I have an UP mini that I've modified both the nozzle and bed to customize the temperatures on.

Bed gets heated to 100˚C and nozzle is either 266˚C for UP ABS filament or 236˚C for off-brand ABS filament.

score 7 · Accepted Answer · answered Jun 01 '16 at 14:12

A couple things to consider:

Ensure that your build plate is flat and level. An un-parallel HBP could result in the object "welding" to the raft.
Turn down your nozzle temperature. It is likely that the material is hotter than it needs as it is extruding. This results in a slower "cool-down rate". So, if it takes longer for the filament to cool between the raft and the first layers of the object. Therefore, cooling together in a manner that somewhat binds them.
Personally, 266C seems VERY high to me. I've primarily only used ABS on my MakerBot and have successfully printed with 225C +-5C nozzle temperature and 110C +-2C HBP temperature.
Typically you want to extrude slightly above the melting point. You don't want to liquefy the material, but make it pliable enough to bond it to other layers of material (or a BP).

score 2 · Answer 2 · answered Jun 06 '16 at 15:02

You could try reducing the temperature of the hotend. If you are using too high of a temperature, the ABS will "run" and over-adhere to the raft.

What slicer are you using? I have found that raft quality is drastically affected by the slicer I've used. In my experience, MakerBot and Simplify3D produce the nicest, easiest to remove rafts. I've also had success with Cura.

Barring changing the temperature of your hotend or switching to a new slicer, you could always try printing without the raft. From the sound of it, your bed is hot enough. Do you have Kapton on the bed? If so, give printing without a raft a shot. If sticking is an issue, try painting a slurry of ABS and Acetone onto the bed before starting.

score 1 · Answer 3 · answered Jun 12 '16 at 02:02

Do you allow the filament to cool completely (5-10 minutes or longer after printing) before you begin to remove the rafter, or do you remove the printed piece immediately after finished printing and begin to remove the rafter?

In my experience, I have noticed that the rafter is easier to remove if the piece is still somewhat warm from the heated bed.

score 0 · Answer 4 · answered Jun 20 '16 at 05:00

I haven't got a printer with a heated bed so have only tested this on PLA but I have found editing the G code so the printer cools the nozzle down and then heats it up again gives the raft enough time to cool down so that it peels off easier when the print is finished.

Raft hard to remove?

4 Answers4