Topic: Need information on 3D modelling / printing (Read 4140 times)

john_k · « **on:** February 23, 2020, 01:38:34 pm »

Hello,

Being as I am, completely clueless about all aspects of 3D printing, I'm hoping the team of experts here can give me a bit of an insight. I need to produce 3D files to print fairly small (25mm. cube or thereabouts) and relatively simple shapes ultimately for use as patterns for investment casting. I have for years used 2D CAD for manufacturing and modelling - this does not seem to be an advantage. I do not think I can use many of the current 3D programs (Fusion 360, LibreCAD) as I think my desktop computer lacks the capability and I have no real ambitions to upgrade just for this purpose. I have Sketchup v.8 on the PC - can any of this produce suitable output? What file type do I need to produce? Should I just give the part drawing to a professional and hang the expense? Is there any 3D CAD system that is economical enough to justify the expense given that it will be rarely used?

Your thoughts and comments will be much appreciated

cheers John K.

Big Ada · « **Reply #1 on:** February 23, 2020, 04:52:49 pm »

It may help if you put your Location, as some one may live near you and could pop round.

Len. ( you can see I am in Kent )

SailorGreg · « **Reply #2 on:** February 23, 2020, 05:05:18 pm »

A while back I needed to replace a simple plastic moulded part about the size of a matchbox (but a hollow cylinder with a flange). With no previous experience, I drew the part in Sketchup and sent the file to Shapeways. They check that your file is actually printable, then print it for you. The part I got back was just what I wanted. Never done it again since, but it wasn't too difficult after some practice. Shapeways tell you on their website what types of file they can handle.

Greg

john_k · « **Reply #3 on:** February 23, 2020, 05:53:48 pm »

Thanks for the replies. We live and learn - I was under the (obviously mistaken) impression that location was included in one's profile. I have added it now. Anyway I am at Boksburg (near Johannesburg) in South Africa.

Further to the enquiry, it begins to look as though an extension would be required to enable outputting .STL files from Sketchup - which I don't have.

kinmel · « **Reply #4 on:** February 23, 2020, 06:21:47 pm »

https://help.sketchup.com/en/sketchup/importing-and-exporting-stl-files-3d-printing
I would export the file, analyse it using Meshmixer to ensure there are no "holes" and then it is ready for your Slicer software to create the .gcode file

JimG · « **Reply #5 on:** February 23, 2020, 08:40:04 pm »

For simple designs a useful free program is DesignSpark Mechanical from RS Components.https://www.rs-online.com/designspark/mechanical-softwareIt is simple to use and doesn't need a lot of experience with expensive cad programs and produces good stl files that print well.
Jim

RST · « **Reply #6 on:** February 24, 2020, 09:45:35 pm »

Checkout tinkecad by autodesk. it's web-based which I hate but it's free. I still can just not make the leap from 2 to 3-D cad but I took to tinkercad in just a few mins, and I tried an awful lot of programs before!

It's not amazing but I tried sketchup before and left in complete bewilderment how anyone could use it nevermind produce anyting from it. I don't have any problems with checking my files are printable but my printers are cheap and so is filament -I just save the .stl then import into cura for my printer and try it. The more I try the better I get. I'm staggered how accurate / small my prints are getting now (albeit not as good as resin / SLA).

I really am anti-tech, but I embrace 3-D printing 1,000% these days, it's a great tool. I tried printing a lot of parts for my mini loyal class this time as an experimental hybrid and it's worked well so far...

Sorry, meant to say tinkercad will output big std .stl and .obj files plus one other I forget which appeared recently. Cura slicer produces the .gcode for printing.

Hope this helps/inspires.

grendel · « **Reply #7 on:** February 25, 2020, 08:09:46 am »

I use AutoCAD, as an ex drawing office manager I cant get my head around the free software, it just wont do what i want and know I can achieve in autoCAD. at work I currently use 2d autocad, but at home I use the free educational version for my 3d work, and I use it all the time, only this weekend I was producing a 2" diameter 7 and 9 cylinder radial engine , basically i created the heads with a hole and the centre boss with spigots to fit the blocks onto, look at the educational version and there are options to sign up as an educator too, I teach my colleagues how to work CAD so thats educating them. thus I have a full version of autocad 19 free, it does everything i want it to, I basically draw the shapes I need as closed polylines, then use pushpull to expand their thickness to what I want, then unite or subtract components to achieve my finished model. then its just a case of exporting the stl file.
If you have windows 10, that has a built in 3d viewer, and can output to a 3d printer and has paint 3d that might work for simple shapes.

warspite · « **Reply #8 on:** February 25, 2020, 11:19:50 am »

So just to be clear - are you creating 3D Solids in autocad, so like the attached 3D solids picture?

grendel · « **Reply #9 on:** February 25, 2020, 01:10:50 pm »

was that question to me - if so yes
this is what I was creating recently

warspite · « **Reply #10 on:** February 25, 2020, 05:20:58 pm »

Sorry, yes Grendal, it also signifies that autocad solids can be used to create a 3D file suitable for conversion to .STL

grendel · « **Reply #11 on:** February 25, 2020, 07:15:18 pm »

yes i just export as a stl directly, never yet had a problem with a broken model that i have drawn up in CAD

richald · « **Reply #12 on:** February 25, 2020, 10:31:24 pm »

I have been using Tinkercad for 12 months - fairly simple - easy to use and quite powerful when you get the hang of it
I'm just finishing off a 3-D printed boat with four (own design) 3-D printed water jets.

RST · « **Reply #13 on:** February 25, 2020, 11:16:24 pm »

Very interested how you generated that hull in tinkercad! Did you use the custom shape generator bit you need to know a bit of programing language for?

richald · « **Reply #14 on:** February 26, 2020, 01:28:18 pm »

Long explanation about the creation of the Hull . . . (the sample picture at the end may help with the explanation)

I got hold of a solid 3D model of a Crackerbox hull (an .STL file) copied it into Tinkercad.
1) Stretched longer and wider until the shape was what I was after.
2) Made a duplicate, shrank that by 4mm in all directions, converted it from a solid to a hole, lined it up with the solid hull and merged the two together to give basically a hollow shell with approx 2mm walls.
3) Chopped it into four pieces (to fit my printer) added joint flanges, cut out hatch openings etc.

The sample picture below shows Tinkercad basic operations
From left to right:
the hole component, the solid cylinder, the two items aligned with each other, and finally merged to give a thick-walled tube.

warspite · « **Reply #15 on:** February 26, 2020, 06:11:42 pm »

You can do something similar in autocad, I generally make the 'hole' component longer so it pokes out of the top and bottom to ensure that a hole is definitely generated.

There is a function in autocad that allows a box to be created with a command 'shell' and it asks how thick the wall and it creates a hollow box, it does have its limitations to do complex shapes but it good for duct work when I used to do arrangements for an air conveying company.

Same for pushing and pulling closed shapes to create an extrusion as Grendel mentioned.

me3 · « **Reply #16 on:** February 27, 2020, 07:46:38 pm »

Google Sketchup can be used to produce the files, you need to download a .stl file converted online as a plugin, easy program to use! Something I made on sketchup..

RST · « **Reply #17 on:** February 27, 2020, 08:25:15 pm »

Thanks richald. If you imported the hull file that makes perfect sense. Tinkercad can't generate that without programing and doubtable if you can do it that we'll regardless. I agree with other comment though. When I create through "holes" I make the nagative shape much bigger. If you follow the blogs they only say .1mm is enough, bit I find that hit or miss and make it much bigger.

RST · « **Reply #18 on:** February 27, 2020, 08:27:18 pm »

Fair play to me3! I could probably get to that in tinkercad given enough time but SketchUp leaves me totally baffled these days! Each to their own as they say.

richald · « **Reply #19 on:** February 27, 2020, 11:40:14 pm »

Yes RST

I make the holes taller and then drop them down a bit to ensure a 'clean' hole -
I just prepped the example very quickly to illustrate what I had been wittering on about
in the previous paragraph!

RST · « **Reply #20 on:** February 27, 2020, 11:54:29 pm »

Quote from: grendel on February 25, 2020, 01:10:50 pm

was that question to me - if so yes
this is what I was creating recently

...Interesting. What outer diameter was that and what layer height did you set if you don't mind me asking please.

john_k · « **Reply #21 on:** February 28, 2020, 12:17:10 am »

Hi,

I've been out of this for a few days. We had a break in at the house and I had to repair damage to the computer from thieves. In the couple of days interval, this thread seems to have gone off by itself. Apart from some of the earlier posts, I don't think that much of the above is really helping me.

Thanks anyway.

RST · « **Reply #22 on:** February 28, 2020, 12:39:35 am »

OK John,
Hope you get things sorted. Problems with forums is for any question you get ten answers!

To be more direct from me:

Tinkercad from autodesk -no brainer as someone who still cant go from 2D to 3D CAD it's the best and free for what it is. I cant go to fusion 365 yet with it's charges
Sketchup -Tried it a few revs over many years, use to try to learn it but then it changed and just binned recent revision -it's awful! it used to be OK but totally crap now!!
What file: -.stl or .obj for printing. You need to then export or drag and drop as I do an .stl file into "cura" (other slicers available) which automatically generates the printing file for FDM anyway called g.code (standard CNC etc code) not sure what you mean by "stable output"? 3-D printing isn't like connecting your device to a printer and pressing "print"

Quote

Is there any 3D CAD system that is economical enough to justify the expense given that it will be rarely used?

...tinkercad for me! I have one printer cost me hundred quid or so -and it pumps out small things every hour every day of the week if needed. My bigger printer so far -hmm much less impressed with!. No difference to the print files for both. Everything is standardised anyway which is great so you can google and youtube to your hearts content for info and guidance. I live off youtube for stuff like ths.

..thank god for those patents expiring a few ears ago! 3-D printing must have een on the go for 50 years now? But now it's all standardised files even a simpleton like me can find a suitable interface and its very easy now!

warspite · « **Reply #23 on:** February 28, 2020, 12:01:42 pm »

John K, just to be clear the output of the autocad file in 3D is the ones available in the export function, you pick the one that your printer uses or the one that a company like shape ways uses (can be various files i.e. .obj or .stl as the extension, the size of the file will be that by the printer or company whichever you use), failing a compatible export format, then finding a converter on line should be simple enough.

As stated, YouTube should give you a greater understanding.

Me personally I use Autocad 3D solids as I prefer the 3D functions in Autocad and to me it's simplicity.

cos918 · « **Reply #24 on:** March 23, 2020, 09:13:57 pm »

need some info please.
I have drawn out a window fram on Tinkercad to get printed. I am only getting one printed a first to check. If thats ok I would need over 50. Do I need to add the sprues to the drawing I upload to Shapways or is there a program that does that .
What do they mean by a Bounding box ? Is that some thing I need to draw or do they add that .

John

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Author Topic: Need information on 3D modelling / printing (Read 4140 times)

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