Trying to print directly on top of inner surface without infill imprint

[JTPrint 0]

Hello, 

 

Im creating a mold where silicon will be poured into it to create a silicon stamp.  The top surface needs to be somewhat smooth or at least consistent looking. 

As it prints along it gets to the surface skin layers inside the mold,  which will be the top surface of the finished stamp. The print will then continue to print the lettering image of what will be the stamp ( so extruding up wards, male) . On the finished stamp this ends up being a void area that does not capture any ink. When you pull the silicon out of the mold the lettering is now female ( void) . 

 

the issue is the program wants to outline the lettering and image into the surface layer, which is causing a ton of imperfections and looks. as the lines go past areasof the image or lettering. As well as alot of extruder head/string pulling marks as the layer goes from letter to letter to fill them in last. 

 

If I basically can get the next layer, which will be the start of the lettering and image to go right on top of a surface layer that is basically straight lines ( no infill lettering imprint) 

 

I've tried mono lines and mono ironing, but really just need the layer right prior to the layer that is creating the words to be a flat layer of solid straight lines.( no infill imprint) 

 

[Slashee_the_Cow 269]

TBH I'm having trouble understanding your problem exactly, you might have to explain it more clearly. But if I'm understanding it:

You can follow my instructions in this post to create a support blocker then make it the right size and move it into the right spot. But instead of using it as infill modifier, you can use it as a cutting mesh to change the settings to 100% infill density, which will draw solid lines in every layer the modifier covers.

Before:

After:

 

You could also set the wall count to 0 and extra skin wall count to 0 so that the area is printed as just surface:

A bit less ugly around the edges if you set the the pattern to zigzag, or smooth edges if you set it to concentric:

 

It might also be worth mentioning that Cura does have an option which turns a model into a mould in special modes:

(Left: regular, right: mould, both: cow)

[JTPrint 0]

From the picture in the first post, the one that say currently. 

This is a surface layer. I have attached the cad drawing in this post.

 

See attached photo in this post. 

 

Imagine having a city block, and buildings build on top of it. The ground of the city block is a finished surface. The building 3d print upwards from it. 

 

My issue arises at the printing of this surface layer. Instead of printing this surface layer blank. Just a bunch of lines connecting the outside  circular shape, say like an initial layer. It also wants to include a pre print of what is going to be printed on the next layer ( this would be lettering or image. See first photo in first post. That "H" is being printed in the surface layer.)  Im guessing it is a pre infill layer? there is nothing in the solid cad model that has an "H" -z into this layer. So it is created by the program to premake for the next layer.  Because it is printing these letters and images, it is causing the surface layer to become all screwed up. It prints a surface and leaves the lettering blank ( like that first photo) then comes back and fills in the those areas. So it is a flat surface, but you can read the lettering and image in the layer.  While doing do the surface lines are uneven, it leaves head marks and strings from printing one letter then going all the way across the model to print another. The lines from one side to the other are uneven. 

 

I want it to print a flat layer with no pre lettering. Just straight lines from one side to the other. Then for it to start the infill and walls on top of this layer.  So basically take a piece of paper and put a can of soda on it. I dont want the pre imprint of the soda on the paper layer. 

 

 

[FredFish 4]

can you create two files, one with the base the way you want it, and the other with the lettering the way you want it, then bring them both into Cura, and offset the z for the top lettering?, this should not combine the top with the base, just print the top on top (providing top and base alignment with the slices z distance), slashee may be able to discribethe processes better, but i have done something like this type of stackup with transparent fillament in the past. 

[Slashee_the_Cow 269]

I was writing this up while @FredFish was typing and their way is much much better:

@FredFish's superior way:

I'm starting with my coin with no head on it:

I've made the head a separate model, so I add that, and move it up to the correct height (which I know because I know how thick I made the coin model):

In the move controls, make sure you turn off Drop Down Model, or else every time you try and move it up it'll just drop back down.

It's that simple! Now a bunch of screenshots which make it look complicated without the disclaimer that it's just showing that it works:

 

 

 

Lookin' good so far. Let's pop down a to the layer below the cow head:

Mmmm, sweet, unfiltered surface lines. Now let's just pop up one layer:

It's now printing just cow head, there's no surface lines from the main coin (if there was, they'd have alternated direction). Shot from the top again quickly:

Yep, that's a cow head printed on top of a flat coin face.

 

 

And in case anyone was wondering, yes, the other side is the tail:

 

 

Stop reading here. My idea sucked.

 

 

 

 

 

 

 

 

What I was going to say that you should probably ignore:

Here's my Slashee coin:

If we go down to the main surface, there's holes for the face:

Then we create a support blocker, turn it into a modifier but for infill only, set the infill density to 100%, make sure the wall count is 0, the skin wall count is 0 and then set the skin wall count for the main model to 0:

The only problem with doing it this way is that it will do the lines for the rest of the skin, and then it will fill in the cow face, depending on your printer and settings that may be noticeable because it will be travelling over skin:

 

Edited November 8, 2023 by Slashee_the_Cow

[JTPrint 0]

This seems to be what I am looking for the fredfish method And What I have to do is similar to the coin example. Will try these out tomorrow. 

 

My last resort was going to be manually removing the skin layer from the G-code. Paste in a plane layer from below it in that spot, and hope the next layer, the first wall layer would just work. Seeing how it is a ton of g code to copy and paste I was hoping there would be a quicker way, in which I think the above maybe. 

 

It would be nice if it was just an option box to turn off this infill. I know you can turn off the wall around this infill, but you I couldn't find an actual box that just says ignore the bottom of the infill only.

[Slashee_the_Cow 269]

1 hour ago, JTPrint said:

It would be nice if it was just an option box to turn off this infill. I know you can turn off the wall around this infill, but you I couldn't find an actual box that just says ignore the bottom of the infill only.

It's sort of a edge use case. There's no reason most people would want to do it, without just printing the whole thing completely solid (or using a modifier to make one section completely solid). You can submit a feature request if you want, though.

[JTPrint 0]

Thank You all for the help. Turned out perfect.