Different fill density for different parts of the print?

[axsdenied 0]

I am trying to print an enclosure with posts that will be tapped so the screws can be used. Unless I use 100% fill the posts are printed in honeycomb with a "circular layer" on the inside and outside. When a tap is used to cut a thread it is not strong enough. Solid fill of the posts would (probably) solve the problem but then I would need to print the whole enclosure with 100% fill. This will take a very long time.

I am probably asking too much but anyway... is it possible to have different fill density for different parts of the print? In my example to print the enclosure with, say, 20% fill while the posts are printed with 100% fill.

I also noticed that in cura changing the shell thickness improves things a bit. The post will have more inside/outside "circular layers" which helps when tapping the holes. However, even if I set shell thickness to a very large number cura still insists to use honeycomb inside the posts.

 

[yellowshark 153]

Well it can certainly be solved partially by setting the solid layers setting to the appropriate amount. Say you want the solid area at the top to be 10mm, set the "bottom/top thickness" setting to 10mm So you will get a solid 10mm at the bottom and a solid 10mm at the top and the area in between will be you infill %.

I would actually make the setting "depth of solid area required" + (2*layer depth).

In addition you need to consider the surface area of the posts. It might be a good idea to make sure that the first few top layers laid down get you a smooth solid surface before printing your 10mm. I am guessing that with a 10mm screw the screw and the surface area of the post are quite small. so an extra 1.n mm should be sufficient where n=0 for .100 and .200 layer depths and n = 2 for .300 layer depths.

For total flexibility on this subject you would probably need to invest in the Simply3D slicer.

 

[eldrick 65]

You can also embed threaded brass inserts after printing: http://www.mcmaster.com/#catalog/121/3303/=visovv

 

[yellowshark 153]

Hi EldRick have you used those inserts? I am just wondering in reality how easy it is to use a soldering iron to stick the plastic to them without damaging the plastic surface; accepting of course that in some scenarios the surface may be hidden.

They also supply a Solidworks parts model which in theory is great although it differs from the picture. Maybe the picture is generic and the Solidworks model specific?

 

[gr5 2,173]

@axsdenied - 3 things:

1) Cura won't do that but the "new" upcoming version code named "pink unicorn" will. But that might be many months from now.

2) simplify 3d can do this. It's not free but not expensive either. And it works well for ultimaker printers:

http://www.simplify3d.com/software/

3) You can get Cura to do what you want if you have access to the cad model. You can add very very thin air tubes (say .001mm) and Cura will print shell around them effectively creating a solid area of your part. Emmet on thingiverse (a damn genius by the way) does this and it works well.

 

[eldrick 65]

I use the insert in my sport-fencing products. They melt into place easily with the soldering pencil and adapter, and none have come loose yet, on the 200 or so that I've sold. When the plastic shrinks as it cools, they are solidly fixed in place.

http://stores.thefencingpost.com/pommel-epee-french-grip-melting-pommel-14g-170g/

This image shows an early version where the hole wasn't big enough or shaped quite right, and a "collar" of plastic was being forced back out. Now that I've had some practice, they sit flush with the surface.

 

[yellowshark 153]

Thanks for that; I am not sure if I am clear. Do you - create a hole in the 3D print that exactly images the dimensions of the insert - after the print poke the soldering iron into the hole and lightly melt the circumference of the hole - quickly insert the insert - job done ? Is it a special soldering iron or can I use mine? Recommended temp. of the soldering iron?

 

[eldrick 65]

If you click the Product Detail for the size you want, they show a hole profile. The insert has a slight flange at the outer end, so the hole is not completely critical.

You use their (Weller) soldering pencil with an adapter-tip that fits in the insert and holds it while heating, heat up the insert, and push it into the hole with the soldering pencil, where it melts and slides into place. I leave a half-mm sticking out, then immediately push the insert flush with the plastic onto a flat metal surface, and when it cools in a minute or a few, it's done.

It's very solid - the fencers use both hands to screw the plastic pommel hard down onto the tang of the blade, and I haven't heard of one breaking yet.

 

[yellowshark 153]

Thanks, got it now - looks a really nice idea

 

[tinydancer 0]

If you click the Product Detail for the size you want, they show a hole profile. The insert has a slight flange at the outer end, so the hole is not completely critical.

You use their (Weller) soldering pencil with an adapter-tip that fits in the insert and holds it while heating, heat up the insert, and push it into the hole with the soldering pencil, where it melts and slides into place. I leave a half-mm sticking out, then immediately push the insert flush with the plastic onto a flat metal surface, and when it cools in a minute or a few, it's done.

It's very solid - the fencers use both hands to screw the plastic pommel hard down onto the tang of the blade, and I haven't heard of one breaking yet.

 

That's genius!

 

[eldrick 65]

Be aware - size matters!

:-P

I'm using a 6mm thread - smaller sizes will not be as strongly embedded, due to the diameter.

 

[yellowshark 153]

D*mn American paranoia. to our American members. They will not sell outside of the USA except to established customers due to "extensive export regulations". Am I really getting access to important defence technology or likely to create a plastic bomb with one of them. Thank God the Corvette parts suppliers in the States do not take the same attitude - actually thinking about that I assume it means actually these people cannot be bothered.

I was told no European distributor I could contact.

 

[eldrick 65]

Now you're being silly - ever hear of Google?

Try searching for Heat-Set Inserts for Plastics Top of the list is Spirol International, which has a UK distributor: https://www.spirol.com/company/products/prod_d.php?ID=57

McMaster is just a parts distributor in the US, not a manufacturer - no need to tar the United States with a broad brush because you don't know how to search on the Internet. If they did ship to the UK, you would be griping about the cost of shipping.

I'm told that industries actually do exist outside North America...

 

[yellowshark 153]

No I am not being silly Eldrick. Why should I waste my valuable time searching for something that you have kindly shared with us. They ship overseas just like all the Corvette parts distributors, from large companies to one man bands, whom all clearly can cope with whatever level of export regs. - for stuff <10$. And yes the freight is heavy But, and this is the important point, they lied to me. But many thanks for saving my time with Spirol .

And God bless America for NFL.

 

[yellowshark 153]

The Spirol "Inserts for Plastic Design Guide" is awesome.

"https://www.spirol.com/library/main_catalogs/ins_us.pdf"

 

[janf 0]

Hello there,

PEM inserts are available everywhere too.

Search 'press in nut' and a world of suppliers will occur.

In the netherlands Onkenhout is the reseller. Every country is represented by PEM I believe.

Succes, Jan

P.S. I print a wall thickness of 1 mm and the hole only 0,2mm smaller then the wanted thread. In most cases this is sufficient.

[yellowshark 153]

Thanks for that Jan. I still have not got my head around printing the insert circle smaller (it will be smaller anyway in the finished print!) and then being able to insert the brass insert.

What temp. do you guys set your soldering iron to in order to melt the plastic when using heat set inserts?