Can PrusaSlicer add a customer support enforcer only above a certain layer?  

It's time to add tailored support in the original design.

See picture: here I would chamfer the cutout then add two support towers (green) and a one layer support sheet (red).

I have drawn it too wide for clarity, the support towers only need 1mm clearance.

Cheerio,

RE: Can PrusaSlicer add a customer support enforcer only above a certain layer?

Diem,

Thanks very much for taking the time to reply. Appreciate the helpful response.

I was coming to the same conclusion as yourself, that I needed to design my own support system, but yours is a far better idea.

One questions is how close does your red support bridge need to be? Is it a layer below so they touch, or two layers below so that there is a layer gap, perhaps 0.2mm, or should I run a series of parallel lines for the top lug to be supported on.

Here's my first design, I'll print it and see what happens

I

RE:

While diem's approach works and is arguably the best solution—in particular if you have control over the model—, you can accomplish what you want to do in Prusaslicer as well. Just don't use a support enforcer. (BTW, the blocker doesn't work because once a support is initiated from the top, blockers don't block regions below, because that's not how they work. ) However, if you use paint-on supports—which I vastly prefer over support enforcers—it'll work as expected.

Also, your comment about height range modifiers "just does layer thickness". Uh, not true. I admit, it's not intuitive to find but if you add a height range modifier, right click on the range in the parts panel, and you'll get a whole slew of additional options. Alas, none of them help with your support issue.

RE: Can PrusaSlicer add a customer support enforcer only above a certain layer?

I just realized that maybe I misunderstood your design intent. If the nut hole in the bottom lug penetrates the whole lug, what I suggested won't work because the support will extend through the hole. However, you can deal with it by painting a small support blocker on the top of the arc, right above the nut hole.

RE: Can PrusaSlicer add a customer support enforcer only above a certain layer?

@fuchsr

Thanks for this. I tried using the paint on supports and they don;t quite work the way I want them to.

I have a square volume in the lower lug. This will hold an M3 Square nut. You can see this here:

I will pause the printer at the top of the square hole at the bottom lug, put a nut in and then continue the print.

The problem is if I paint on the supports as shown below

and then slice. I get the bottom square hole with support material as well

You can see the square with the green support material.

I am not an expert in PrusaSlicer and if there is a way to paint the supports so that they only go upwards and not downwards, please point me to the right place.

PrusaSlicer does seem to do an awful lot, but it does rather hide its functionality. I can see why, but itif I can do what I'm after any otherway, I'm happy to try.

Currently I'm printing test supports to see how they look and work.

Appreciate all the help and if there's a page someone can point me to, I'll happily look there. I did spend a long time looking though.

Thanks

Rob

RE: Can PrusaSlicer add a customer support enforcer only above a certain layer?

That's a more tricky situation because with paint on supports, PS treats the top surface of the insert hole as a legitimate start point for new supports. You'd have to use the clipping function to expose that surface and paint a blocker on, but I found my hands to be too clumsy to get the clipping tool to do what I want to…

One questions is how close does your red support bridge need to be?

As this is a functional part and the cosmetic affect is unimportant I would make the support bridge sheet itself the bottom layer of the upper part.  Then break off the support towers and a quick pass with a sanding block to tidy the edges.

Cheerio,

RE:

@diem,

I'm working on the bridge you suggested. I have the bridge designed and thats fine. It's a little tight but got the bridge OK. I have a series of thin supports on the top and this is the area I'm working on. I'm trying to work out how thin they can be and how far apart they can be. I can use a scalpel to cut some of it and sand as suggested but my supports aren't as good as the ones PrusaSlicer creates. This is the latest version as I try to create as few supports as possible.

Getting there (but slowly)

I'm trying to make this as easy as possible to break off as this is not a one off.

I really do appreciate the input here.

Thanks

Rob

Your support is much more massive than needed.  It only needs to take the weight of two or three layers, after that *this part* will maintain itself.

Cheerio,

RE: Can PrusaSlicer add a customer support enforcer only above a certain layer?

Hi,

Apologies, only just seen this. The issue for me is that if I turned the clamp over so the nut hole is on the top, that affects the other side of the clamp in much the same way 🙂 However I now know how to do support blocking through painting.

Posted by: @fuchsr

I just realized that maybe I misunderstood your design intent. If the nut hole in the bottom lug penetrates the whole lug, what I suggested won't work because the support will extend through the hole. However, you can deal with it by painting a small support blocker on the top of the arc, right above the nut hole.

RE: Can PrusaSlicer add a customer support enforcer only above a certain layer?

@diem, yes you are correct, however when I was designing it, I had issues with first layer adhesion and so I created it larger with a larger footprint to get the thing to stick.

I'm going to get the top vanes working so it is supported correcttly, then I'll reduce the size of the support bridge to something smaller. I was using PLA on a Satin sheet initially, but am now back to PETG on Satin sheet, so things are sticking better now.

I'll get the size down at the end.

Thanks

Rob

Posted by: @diem

Your support is much more massive than needed.  It only needs to take the weight of two or three layers, after that *this part* will maintain itself.

Cheerio,

RE: Can PrusaSlicer add a customer support enforcer only above a certain layer?

@ringarn67

Thanks for this. I have done what you sugested and am laughing as I have absolutely no idea what you have done, how and why, but it works. I have support between the lugs AND a square volume inside the lower lug that doesn't have support.

I looked at the F360 file and can see that have created a square volume inside the lower lug with a cylinder coming through. That matches what I have.

The rest of what you suggest is much the same as me trying to explain compiler design to my dog 🙂

I will need to unpick what you have suggested and why so I can understand it. This is way beyond what I have ever done, I have never looked at "Snug" in "Print Settings" -> "Support" -> "Style".

I think (but could be wrong) I can see that changing the infill to 0% and top and bottom parameters to 0, fools PrusaSlicer into thinking that there is something there and therefore no support is needed, when in fact there isn't.

I'm genuinely impressed with this. I am still laughing and shaking my head as this is nth level hacking and I'm still at Level 0.

Let me read and learn, and I'm delighted that I have something new to think through.

Many thanks

Rob

RE: Can PrusaSlicer add a customer support enforcer only above a certain layer?

Posted by: @rwillett

@ringarn67

Thanks for this. I have done what you sugested and am laughing as I have absolutely no idea what you have done, how and why, but it works. I have support between the lugs AND a square volume inside the lower lug that doesn't have support.

I looked at the F360 file and can see that have created a square volume inside the lower lug with a cylinder coming through. That matches what I have.

Feel free to ask and I will try to answer the best i could. I know my F360-file is a bit clumsy, I just wanted to test it as fast as possible 😊 

I will need to unpick what you have suggested and why so I can understand it. This is way beyond what I have ever done, I have never looked at "Snug" in "Print Settings" -> "Support" -> "Style".

"Snug" keeps the support tighter, with style set to "Grid" support will swell out a bit. If you change between them difference is pretty obvious.

I think (but could be wrong) I can see that changing the infill to 0% and top and bottom parameters to 0, fools PrusaSlicer into thinking that there is something there and therefore no support is needed, when in fact there isn't.

That is exactly what I think is happening. 👍

Many thanks

Rob

Your welcome, and thanks to You I learned something new

RE: Can PrusaSlicer add a customer support enforcer only above a certain layer?

I've rebuilt the Fusion 360 file to work with the sacrificial part. This is the whole pictiure

and here's the lower clamp with the sacrifical part in place

I'm printing now to see if it all works with captive square nuts

RE: Can PrusaSlicer add a customer support enforcer only above a certain layer?

So here's a pic of the captive nuts going where the void would be. There will be two more each piece that are vertical/