cleaning up print failures

[The Fatadder]

Last night I set a new design for a GWR O5 siphon to print is first test, ended up with a minor failure where the centre inch and a half of supports failed to print.  Net result was that the solebar failed to print properly along the bottom.  This is the second time I have experienced this issue, last time (with a different drawing) I put it down to some marks on the centre of the FEP.  I cant work out what has gone wrong to cause these (I dont usually drain the tank between prints unless there has been a failure, and its hard to see them through the resin).  However there have not been any failures since I changed the FEP about a month ago (until today).   

 

Yesterdays print was perfect, making it all seem a bit more strange.

 

Given the cost of a new FEP I dont want to be changing it every few weeks (particularly as they are like gold dust), I managed to brake one of them trying to remove a protective film that didnt exist last time.  As ever the OEM part is looking hard to source so ideally I am trying to see if there is a way of removing this damage without ruining the FEP.  (It would also be good to hear any suggestions as to what might be causing the damage in the first place)

 

 

Edited May 17, 2022 by The Fatadder

[The Great Bear]

So microfibre cloth and IPA or other cleaner and careful use of plastic scraper won't remove, Rich? When I was printing I don't recall having failure with residue on the fep that I couldn't remove, although such failures do wear the fep.

 

Does your printer have a special fep sheet rather than a plain sheet secured in place, then? If so that's a pain prevents buying cheaper generic fep sheets.

 

Print does look very good. Hope you get issues resolved.

 

Jon

 

 

[The Fatadder]

I gave it a soak in ipa but no luck removing the damage, so I’ve taken the hit and ordered another pair of FEPs from 3dprintermonkey.Co.uk with delivery due tomorrow (along with new bolts for the tank to replace the one with the stripped head.)

 

it looks like it must be down to minor failures which are not easily apparent on the finished print.  It’s an odd one as it must be very thin, as opposed to the thicker failure where something hasn’t stuck to the plate. 
 

i think the issue also may be related to my china  clay TTA print, all be it each time I’ve printed it the drawing it has been different. Thankfully one more print and I’m done with that!

Edited May 17, 2022 by The Fatadder

[Quarryscapes]

You need to start putting proper rafts under your prints, at least when you get fails it's then simple to get off the FEP. Getting tiny little dots like that off is nigh on impossible without deforming the sheet. 

[The Fatadder]

12 minutes ago, Quarryscapes said:

You need to start putting proper rafts under your prints, at least when you get fails it's then simple to get off the FEP. Getting tiny little dots like that off is nigh on impossible without deforming the sheet. 

 That’s part of what I can’t understand, everything I’ve printed has a raft (which has printed correctly). 

[EDDY100]

When I get a stuck print I use an artist's spatula, the finest one you can find with a rounded end. Gently feel around the stuck resin until you find an edge and gently prise it off. Quiet often fail to put enough supports in then you get the resin stuck to FEP problem.

[EDDY100]

Are you using the same style rafts as in picture? My supports of choice is Chitubox default printer settings, thin supports at 70-80% and a few more on flat surfaces if required. Also make sure when you level your your printer that the plate is not too tight to the FEP.

[The Fatadder]

 

This is pretty much the same as I was printing before, I’ve just doubled up with a second wagon this time.  Still haven’t fitted the new FEP so will wait till tomorrow to try printing it

 

Other than the area where the fep was damaged and the supports didn’t print (damaging the solbar), all the body detail printed fine.  It’s just this slight residue on the centre of the build plate that has been causing the issue.  
 

im going to drain the tank and give it a proper inspection once the print is finished this time. 

[monkeysarefun]

Your FEP must be tuned to 330HZ!

 

(Thats the kind of advice that made me abandon Facebook printing groups)

 

If I have residue left on the FEP, I just stick the vat  out in the sun to set, then gentle pressing on the underside of the FEP usually causes the now rigid residue to pop off, or at least lift up enough to get a fingernail etc under it and help it pop off. 

 

 

[The Fatadder]

Will give that a try with the one I’m removing as a test to see if it can be recovered

[MikeTrice]

The supports on the tank wagon look odd. The lower supports seem to go through the raft. The other thing to check is that the model that fails to print correctly is actually sitting on the base and not floating above it.

[The Fatadder]

36 minutes ago, MikeTrice said:

The supports on the tank wagon look odd. The lower supports seem to go through the raft. The other thing to check is that the model that fails to print correctly is actually sitting on the base and not floating above it.

The tank is hollow ( with supports going inside) and sits on a triangular spar running along each side (with supports below it).  This helps stop the pull force through the supports distorting the thin outside of the model).   There is a cross piece at either end to keep the two spars the correct distance apart (supported from below).

 

This should show it better:

Edited May 19, 2022 by The Fatadder

[MikeTrice]

It is the bit here. It looks as if the raft is too small or the extra supports have been added later:

[The Fatadder]

I think I may have added that end supports after printing the previous attempt, but the other end also shows the same with supports outside the limits of the skate.

 

It is one of the things which really bugs me with Chitubox that its so inflexible for changing the size of of the skate.  I cant understand why there isnt just a couple of boxes for the X / Y dimension so that you can manually override it.  I want to extend the skate's length (to encompass the bases of those end supports)  but I dont want to impact the width as I want a gap between two prints on the build plate (seeing as I am using it at its limits to fit two prints on at once).  I think I can use the raft area ratio function to change the size (im sure ive done this before, but its not doing anything now)  but that will just make it wider as well as longer

[JimFin]

A trick I use to remove residuals from the vat is to leave a small amount of resin just covering the whole of the fep and run an exposure test for about 20 seconds. Remove the vat and press gently  on a corner of the fep from the underside and on top, use a plastic spatula to gently lift out the entire sheet of exposed resin complete with any residual material attached to it. Refill the vat and off you go.

 

Alternatively you can put some scrap support material leaning on the edge of the vat into the exposure area before running the exposure test to give you something to lift the sheet out with.

Edited May 19, 2022 by JimFin