Recommendations on printing partial hole

[saline 0]

I'm trying to make this type of part where there is a post on one side and a counterbore on the other.  I can place it counterbore-side down, but how do I take the support out?  Any ideas how to approach this?  The actual part will have multiple posts and counterbores.

[GregValiant 1,411]

I dabble in post processors.  I call the one for this situation "Support Interface Material Change".  It can be a pain and cause a lot of pauses and filament changes, but for flat surfaces like you have there the support comes right out.  It would be a real plus if all the support-interfaces ended on the same layer.  If that's the case then only two pauses would be required.  Not bad at all.

This support was pulled out of a model with a cavity on the bottom.  You can see how large and intact it is.  A flick with a screwdriver and it popped right out.  The "first layer over support" looks great as well.  The print was PLA and the support material was PETG.  They don't bond together very well which makes them a good combination for the top layer of the support-interface.

This came out so well I'm using it as a glue mixing station.  There was one pause to switch to PETG for the interface and a second pause to switch back to PLA.  The script handles all that and you just need to pull one out and put the other in.

It's also necessary that your printer can stop when it sees one of the pause commands (M0, M25, @PAUSE, etc.).

 

What it's not good at is large horizontal holes.  There are too many "top interface" layers and so there are WAY too many pauses.

I'll post it if you are interested in going it that way.  If your counterbores are all different depths it would be more annoying than good.

[Slashee_the_Cow 488]

It's worth having a look through different support types as well. Trees can be pretty easy to remove from large surfaces if you disable support interface:

Just remember that small scale testing is your friend - if you're going to see how easy a kind of support is to remove then just test it on a post with a single hole.

 

Thinking slightly more outside of the box, where is smoothness most paramount? If it's "the post and the counterbore" then consider printing with the counterbore facing upwards, so only the horizontal surface the post extends from needs support - and it's much easier to remove support from an exposed horizontal surface than from a recessed round one.

 

And thinking slightly more "into the MacGyver"... print it in multiple parts and glue them together 😄 Cyanoacrylate (plain old superglue) works great on PLA, although I have no idea what you're printing with.

[jaysenodell 18]

I think I'm a user of @GregValiant script. I would suggest using it. It really does make pulling the interface out of tight areas easy. Key notes
* You need incompatable types for the last layer.

* You need to know which layer is last (I still monkey that up on occasion

* You need to get the noz purge right post change or you might get "some stick"

 

Other than that it works as advertised. 

[DivingDuck 105]

An other way, if you don't want to change materials, is printing the part on a 45° angle. Use brim with a light support for the next two or 3 layers and don't print fast.

[Slashee_the_Cow 488]

44 minutes ago, DivingDuck said:

An other way, if you don't want to change materials, is printing the part on a 45° angle. Use brim with a light support for the next two or 3 layers and don't print fast.

Points for the outside-the-box thinking but the problem with doing it that way is it's no longer dimensionally accurate.

[DivingDuck 105]

I use it quite often for my use cases if I need to have good bore features with flat surfaces like in this model. In addition, it provides for the cylinder feature and the section between cylinder and bore more stability in adhesion against sheering. That's why I gave this hint.

 

Apropos dimensional accurate, I would guess it is good enough for 0.1 to 0.15 mm in dimension depending on what dimensions the part have and the nozzle is (beside of the material question). If I need better I would use post processing or a better suited process like cnc milling on first place. Anyway, it is only guesswork as I don't know for what the part is for, what specifications it need to hit. 🙂

[GregValiant 1,411]

I made a couple of minor changes to it so I'll post it again.

• Added a popup message to let the user know if there was no "SUPPORT-INTERFACE" found on any "layer of interest".
• Added "Support Speed" factor using M220.  Now both the flowrate and the feedrate of the interface can be specified.

SuptIntMaterialChange.zip

 

[DivingDuck 105]

@GregValiant

an interesting plugin you have...

Saved for future use cases. Thanks a lot.

[jaysenodell 18]

@GregValiant do you have a repo somewhere?

[GregValiant 1,411]

I have enough trouble keeping track of my post-processors on my own PC much less some remote site.

Some (like SuptIntMatlChange) aren't suitable for Cura.  They require a user to actually "think".  I've done re-writes of several of the stock scripts and I like them.  Scripts like "Search and Replace" and "Insert at Layer Change" will likely end up in Cura.  Maybe in 5.8.  I'm still putzing with "Pause at Layer" but it looks good and maybe I'll do a PR in the near future.

 

Here is a collection of posts I've stuck into a single file.  I'll let you folks look.  Mostly they are little-used utilities that are really handy when you need them.  Others like "Add Purge Lines to StartUp", "Circle around to Layer Start", "Unload Filament at end of Print" I use all the time.

"Add purge lines" has options for where on the build plate you want them.  If a print goes all the way to the left you can move the purge lines to the right edge (or front or back).  It requires that any purge lines be removed from the Cura StartUp Gcode or it will double dip.

I could use some feedback on "Little Utilities v19" so here it is.  Even Slashee-the-Cow got in the act with her "Number the Layer Lines" script.

 

LittleUtilities_v19.zip

 

 

 

 

Edited June 15 by GregValiant