General Red Issues / Learning

A lost wax capable resin tuned for 70 - 200 micron slice thickness
Julian
B9 Maker
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Posts: 24

General Red Issues / Learning

Post#1 » Tue Jan 13, 2015 5:35 pm

New user. After a failed build and some advice elsewhere here I managed to get my first complete build. 95% happy and need to learn a bit more about the resin. I guess I am asking Q's already asked but difficult to find answers by searching sometimes - my apologies in advance for this.

The parts attached 95mm long in line with X axis. 30mm tall and walls of 1mm to 3mm. Standard Red and Standard build settings. Obviously 70micron X-Y and 75micron layers.

The part was built directly from the platform, no supports.

Good - general build / no banding in Z.

Issues
- parts had started to warp, the ends had started to detach from plate, but still firm where attached.
- the odd step over once or twice near the last 8mm of build. Could be machine movement but could be related to warping
- the vertical corners were rounded off where they should be square (but focus is good, IMO)
- outer vertical edges are curved, warped

So; I am not sure what to do about warping or the vertical sharp corners (horizontal corners are much sharper).
Is the corner thing related to light bleed? Would thinner layers / shorter exposure help?

Many Thanks

Julian
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Robert Howle
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Re: General Red Issues / Learning

Post#2 » Tue Jan 13, 2015 7:13 pm

Need to talk with Brumbaer, he is a model builder.
Dance like nobody's watching!

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Metalcaster
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Re: General Red Issues / Learning

Post#3 » Tue Jan 13, 2015 9:56 pm

Usually, you can get some warping and/ or loose corner if the part is not flush to the table. Even I occasionally have trouble getting a long part to stick to the table from one end to the other. I have to magnify the area of contact when I do it and check all around the part to make sure it is level on the platform...( B9 software has this ability)
The other thing is you can add a base to your model in the B9 software..
Another reason you can get warping and a loose corner or 2 is if the platform is not perfectly flat.
Take the platform off the machine and put a flat ruler diagonally across both ways using the thin edge of the ruler and see if it can rock just a little... If it can, then it is not flat and most likely that is the side it comes loose.

These are just some thoughts I came up with at midnight ( Need a smilies for "TIRED" :)

Julian
B9 Maker
B9 Maker
Posts: 24

Re: General Red Issues / Learning

Post#4 » Thu Jan 15, 2015 4:52 pm

OK. Thanks for the quick replies.
Will seek out BrumBaer, but cannot find out how to send a message! Technology!

I have done an experiment tonight; same part but with the "windows" cut in (with supports).
On the one side, large windows, very little warping and nicer build.
On the small window side, warping and distortion leading to misalignment in the build. This end of the build came away from the platform again.
Also built 4 small corner pieces, these stayed attached well no contraction and produced a nice build.

I checked the focus, had a play around and got sharper vertical corners. Not perfect but better.

So, contraction / shrinkage is a linear coefficient (?) the 95mm length is pulling the ends in on themselves. I understand this, makes perfect sense; any ideas to minimise or remove this? I will try a better base as suggested next but wanted to avoid the cutting off / clean up after build.

Any alternative resins / mixed resins available to help with this?

The platform is flat, as good as you could get with sheet metal I think - may be a machined extrusion would be better?

The warped parts from a couple of days ago are improving over time - I read that this happens as full cure is reached post build.

Thanks so far, look forward to your comments

Julian
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Metalcaster
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Re: General Red Issues / Learning

Post#5 » Thu Jan 15, 2015 7:50 pm

You may want to increase your settle times to 4.0. This may help quite a bit. Also, put the part at a slight angle... detail leaning backwards a bit and add supports to the side that is no longer flat on the platform. Also add supports from the base to the back side which is leaning the correct way for that to happen.

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