Acetone is fine for parts that don't require dimensional tolerance. But parts that are meant to mate together may not do so after Acetone treatments as it does melt the surface slightly.

Totally agree, lucky I work in a lab and have had time to refine my technique ;-}

carl_m1968 wrote:

tonyno wrote:

We were discussing the bottom of parts, not that whole part. That was one of my first, so...

But your settings could have an impact on your bottom layer. If you are over extruding that would make your bottom layer much wider than it should be. Also every print I have ever done in my years of printing has had a slight flange as you call it. that is the way it is supposed to be. All your prints require post processing in the form of trimming or sanding the flange and then filling the lines if desired.

A 15-20min cold acetone vapor finish cleans all that up nice as well.

Acetone is fine for parts that don't require dimensional tolerance. But parts that are meant to mate together may not do so after Acetone treatments as it does melt the surface slightly.

tonyno wrote:

We were discussing the bottom of parts, not that whole part. That was one of my first, so...

But your settings could have an impact on your bottom layer. If you are over extruding that would make your bottom layer much wider than it should be. Also every print I have ever done in my years of printing has had a slight flange as you call it. that is the way it is supposed to be. All your prints require post processing in the form of trimming or sanding the flange and then filling the lines if desired.

A 15-20min cold acetone vapor finish cleans all that up nice as well.

We were discussing the bottom of parts, not that whole part. That was one of my first, so...

But your settings could have an impact on your bottom layer. If you are over extruding that would make your bottom layer much wider than it should be. Also every print I have ever done in my years of printing has had a slight flange as you call it. that is the way it is supposed to be. All your prints require post processing in the form of trimming or sanding the flange and then filling the lines if desired.

The first layer is normally wider/thinner  to help with sticking.

You may not be set up like that.

What software and settings are you using?  To be honest that looks horrible from top to bottom.  The layers are way to pronounced and visible.  It looks like you are majorly over extruding.

You may not be set up like that.

Well, if you don't want that "flange" on the bed-side from the flatter layer, rafts are great. Not had any problems to far.

Im not sure what you mean...flange to me implies that the bottom layer has a lip of some sort...mine dont seem to be outside the parameters of the model....and I often sand the bottom a little anyway depending on the print.

Well, if you don't want that "flange" on the bed-side from the flatter layer, rafts are great. Not had any problems to far.

The rafts leave marks on the model.  I often design a model with the bed side or bottom being the top.  The marks that a raft leaves would be unacceptable.  The skirt as it is called can be easily removed.  If there is a Ridge left an exact and a quick pass over a sanding pad cleans it right up.

The only real reason for a raft is if you have an issue with your machine where you just can't get the bed level.  The raft was never intended to be used on a level machine and should never be needed or used in the case of a level machine.

In fact if your machine is level and properly set up you should be able to print Abs directly onto bare glass. I can do it with small to medium parts.  On large parts I still have to use glue.  That is due to the none uniform heating of the Da Cincinnati bed.

I'm new to this, as I just bought 2 da vinci 2.0 printer last week. I teach in a high school in Idaho and am having issues with the parts sticking to the glass. I clean the heck out of it and I still have problems with the glue sticking. any ideas.

Yep...purple glue sticks...and DO NOT CLEAN the bed well when done...just scrape it front to back and left to right a bit to smooth it out a little with a razor blade and re apply the glue after dusting it off.
Make one of these  to catch your waste...

https://tinkercad.com/things/bp3kD7UNlyh

In addition; don't print rafts, I have not come across a print that NEEDED a raft yet (took me a month to figure that out)
Good Luck!

I'm new to this, as I just bought 2 da vinci 2.0 printer last week. I teach in a high school in Idaho and am having issues with the parts sticking to the glass. I clean the heck out of it and I still have problems with the glue sticking. any ideas.

Have you adjusted your bed height properly per the manual process stickied in this section?  The autocal in the machine sets the bed too far from the nozzle.

Also throw away thr UHU glue that came with yhe printer.  Go buy Elmers Purple glue sticks. They dry clear but being purple allows you to assure proper coverage of the print area.