Warping at the base....is this normal?

[ianmellor 0]

Hi all,

I have just bought an Ultimaker 2, dipping my toe into the waters of 3D printing and having lots of problems.

The first and main problem is warping.

Anything of any size that I build seems to warp.

Currently we are using ABS (supplied by Ultimaker) and I'm printing the stacking cup that comes on the SD card.

I changed the material selection to ABS (but not the settings).

I have not changed any other settings.

I cleaned (with water) and dried the build plate and rubbed it with the glue stick (when cool with just a light even rub).

The bed height was calibrated using the normal procedure just before the build.

The room temperature is a nice even 20deg C.

Butt after doing this the part is lifting all around the edge so now it is only stuck down in the middle of the cup and it might not make a very safe cup. Another print warped like a banana again at the bottom in ABS. It seem like it stick down nice for the first couple of mm's but then when it gets higher it starts to pull-up around the edge.

Please do you have any ideas what is going wrong or what I can do about it?

Thanks

Ian

 

[gr5 1,761]

This is a difficult issue. I am not an ABS expert but I have read other's posts.

BRIM

First of all make sure you use the Brim option which is critical and make sure that you use lots of it - maybe 10 passes of brim (qty of brim passes in the expert menu). Brim is on the first basic settings screen in a dropdown. Without brim corners are particularly bad as all the lifting force is concentrated there. Brim helps spread this out but has other uses.

SQUISH FIRST LAYER

A picture would help, but the point is you want to squish that first layer in really well into the glass so there are no air pockets. If first layer is .3mm and nozzle is .4mm you should see the traces squished down wider than tall and flat on top.

HEAT

Unlike PLA, the glass temperature of ABS is much higher around 100C and so the part shrinks much more than PLA when cooling from 100C to 20C. The temp even just 3mm above the heated bed is not much warmer than room temp. So enclose the front of your machine with some clear plastic wrap and find a large cardboard box that can cover the top of your UM2 without touching the bowden. Enclosing the front alone will help. Make sure that your bed is 100C to 110C for good stickiness also.

FANS

Fans should be at 0% for ABS (off).

STICK

I have heard people say that hair spray on glass is better than glue stick on glass. Certainly if you use glue stick you might get some improvement by wetting a paper towel and spreading it more thinly but I'd try cleaning it all off and starting with hairspray. Also cleaning all old oils and such off the glass with water (or even better with glass cleaner) and a rag can help quite a bit also.

 

[gr5 1,761]

Alternatively you can use the "raft" option instead of brim. This spreads the forces more evenly and allows a little bit of movement/warp without lifting off the bed but it results in an ugly bottom surface and is not used much anymore. It is a historical solution that worked well until people discovered ways to get it to stick almost as well and look much better.