3D printing - has anyone used 'SketchUp'?

[Dan110]

Hi all,

I'm thinking about having a go at creating a few bits and bobs that might be useful around the house and having them printed by shapeways or similar. Just fairly simple stuff to start with.

I'm a complete novice and have no experience on CAD or similar but I already have SketchUp and i've spent a few hours playing with it. Shapeways seem to accept sketchup files.

I know there have been a few mentions of this in the technical forums but i just wondered if anyone has any tips specifically relating to novices and online 3D printing services - any recommended apps that make it easy or am I better off putting the time in on a more complete programme? Any good or bad experiences with particular retailers? I quite like the look of shapeways' 'print it anyway' option just because it might provide a usable product despite errors in the design.

Thanks for anything you've got!

Dan

[Simon_CSK]

Dan

I have worn out my 3D printer as I have used it constantly for a year and a half. What I would say is that if you don't have one buy one they are reasonably cheap I got mine for £450 but the last time I looked it was £380.

I have 20 years using CAD both 2 and 3D but this is a new thought process entirely as you need to consider the thickness of the filament when you are printing and you need to make sure that everything is built from the platform up and if there are cantilevers how they are supported during printing.

Great fun but have made about 80% duff to 20% useful models so it is best to have the printer beside you as you will find the models will evolve even if you are sure of what you want. Guaranteed it will look different once you have the prototype in your hand.

[Dan110]

Hi Simon,

That's helpful, thanks for that.

I can see the benefit of being able to quickly test and make changes....I'd love to buy one but I think at the moment i'd struggle to find even £380 worth of uses - it's more just playing with the idea to see if I can make useful doodah's.

Maybe it's just not well suited to the mail-order approach for a novice. Food for thought.......

[Cynic-al]

I used to use a bureau at work before we bought a printer. The advantage is you have a wider range of maerials and processes at your finger tips and you don't have any of the setup and maintenance hassle. I sent them an stl and about a week later the parts turn up.

The down sides are several iterations of a part meant things were taking a long time and back then half a dozen parts could set you back a thousand quid. When you consider that the final part doesnt exactly match what you injection mould and it didn't throw much time or financial advantage to just having a mould made.

We invested in an object, no more expensive than we were spending on bureau but a much faster way of getting several iterations.

If your buying a machine one that can print undercuts makes your life a lot easier but with a bit of thought it's no barrier as you can always cut drill and sand after printing.

If you want the odd bits printing on our machine if you can send me an stl I can cost it pretty easily.

[Dave W]

I took the plunge a few months ago and bought a cheap 3D printer from China in DIY kit form. Total cost including shipping and customs was £200. It's been well used since then and I've produced all sorts of items, some of which I've been wanting solutions for for a few years.

You can get really good quality prints out of the RepRap design printers and there are a number of improvements you can make yourself by printing out different part designs. My most recent upgrade is to a better hot end that will allow me to go up to much higher temperatures, allowing the printing of nylon and polycarbonate objects when needed. I'm currently printing a new X-carriage which will convert the printer to dual extruder, allowing the use of PVA in one extruder to print water soluble support structures. If you're just printing using PLA, ABS or similar (less than 260 C) then the MK8 extruder and hot end that comes with the printer is very good.

As for software, I pretty much exclusively use OpenSCAD to create my designs. It's not too difficult to learn and has the major advantages that you can resize/adjust an element of a design very quickly and it's almost impossible to create a bad 3d print design from it. I prefer it to traditional CAD packages because it's simpler, for me, to create 3D objects simply by putting their sizes into a script. The .stl files it produces have a 100% success rate so far when printing. It's probably not something you'd use for general CAD work but for 3D printing it's pretty solid.

I use Cura to do the slicing of the .stl file and creating the .gcode, again, I tried quite a few before settling on Cura and Cura has given 100% printable gcode including good support options to allow printing of some pretty complex designs.

[Dan110]

Thanks both for the detailed replies and Al for the offer.

More to think about, but £200 is starting to sound like good value.

This is all currently prevarication when I should be either at work or studying so I reckon i'll have a little play with a couple of the free design programmes, maybe send one to be printed so I can get a feel for the results and revisit it after my final due-dates this September when my life is my own again!

Cheers again

Dan

[simonr]

Onshape CAD is worth a look too. It's quite like Solidworks in terms of capability and gives you easily modifiable models.

Sketchup (Stitchup) is worth avoiding unless you are a masochist.

Si

[Dan110]

Onshape CAD is worth a look too. It's quite like Solidworks in terms of capability and gives you easily modifiable models.

Sketchup (Stitchup) is worth avoiding unless you are a masochist.

Si

Ha ha. Cheers for that, i'll check it out.

Does the free account have any limits on use/functionality? I don't mind paying for good software but $100/month for the Pro version wouldn't make sense for me.

Cheers

Dan

[Dave W]

The free account is probably all you need, you can do an awful lot with that.

The problem with OnShape for eventual use with 3D printing is that it tends to produce odd results in the .stl if you're not careful how you build it. I did a CAD design in OnShape for my Sankey conversion and it was great for producing the drawings for the steelwork that I passed to the fabricator. When I tried to do a scaled 3D print though it failed to slice properly due to the polygon designs it produced, I ended up having to build the 3D print design from scratch.

[UdderlyOffroad]

I've mentioned it in other threads but have a look at Fusion 360 as well as Onshape. It's Autodesk's Free-for-home-use-and-SMB version of Inventor. I haven't played with the 'CAM' capabilities in it yet but there are plenty of people on youtube posting tutorials.

Matt

[simonr]

The free account is probably all you need, you can do an awful lot with that.

The problem with OnShape for eventual use with 3D printing is that it tends to produce odd results in the .stl if you're not careful how you build it. I did a CAD design in OnShape for my Sankey conversion and it was great for producing the drawings for the steelwork that I passed to the fabricator. When I tried to do a scaled 3D print though it failed to slice properly due to the polygon designs it produced, I ended up having to build the 3D print design from scratch.

I've not experienced this - and in fact have used it to import files Solidworks has struggled with (Inventor mostly) then exported as STL. Having had a look, your right! But only when you scale a model. If you export full size then scale it in the printer software, it seems to slice OK.

The only difference between the paid and free versions is the number of private projects you can have. The functionality is identical!

Si

[Anderzander]

Thread revival :

I want to make four of these:

Is this worth me trying to find somebody to print or am I better off just trying to find a block of nylon to cut ? 
 

If it was printed I could prettify it by having a radius instead of those two leading edges ....

[Dave W]

1 hour ago, Anderzander said:

Thread revival :

I want to make four of these:

Is this worth me trying to find somebody to print or am I better off just trying to find a block of nylon to cut ? 
 

If it was printed I could prettify it by having a radius instead of those two leading edges ....

You need to decide on material and time. It's a very simple design and not particularly large but on order to 3D print it you'd really need to know what environment it would be used in and what loads would be on it.

3D printed items aren't normally solid and tend to be stronger in one axis than another so the context needs to be looked at, if it's simply a supporting block where the load is in compression then a heavy load would need a finer infill than a light load. FDM printing, the normal hobby printers for larger items, uses an almost continuous filament to print each layer and then relies on the heat for the filaments to melt together when one layer is placed on another and that does effect the strength when it comes to shear forces.

The temperature, UV exposure and any required flexibility would determine the material to be used. PLA would be no good if it is  exposed to warm or hot temperatures as it will soften and is prone to UV breakdown. PETG has better heat tolerance and UV resistance but can be more flexible than you'd want for some applications. Nylon is a PITA to print with but does give very strong results. ABS is good but difficult to print and smells when printing so can meet resistance from other members of the household

On the face of it though it's a simple design and wouldn't take much to print it.

[Dave W]

mainHeight = 45;
mainWidth = 35;
mainLength = 51;
stepHeight = 18;
stepLength = 27;
boltDia = 12.5;
boltYOffset = mainLength - stepLength - boltDia / 2;

difference() {
    union() {
        // Bottom block
        translate([-mainWidth / 2, 0, 0])
        cube([mainWidth, mainLength, mainHeight]);
        // Top block
        translate([-mainWidth / 2, mainLength - stepLength, mainHeight])
        cube([mainWidth, stepLength, stepHeight]);
    }
    translate([0,boltYOffset,-1])
    cylinder(d = boltDia, h = mainHeight + 2, $fn = 100);
}

The above is an OpenSCAD design from your drawing, I assumed from the pic that the bolt would be positioned right at the edge of the step. The strength of OpenSCAD is you can adjust the parameters at the top of the file as you want. To move the bolt along the Y axis just change the boltYOffset value.
Note that you should normally make allowance for bolts, printed at 12mm dia you'd probably find you'd need to drill it out or file it so it's normal to add a bit of extra wiggle room, hence I made it 12.5mm instead of 12mm  !

Edited June 16, 2020 by Dave W

[Anderzander]

Wow Dave - you’re a hero !

Its actually just a shape to hold my door tops against the capping in the back of the 80, whilst they are strapped at the top. Loads and temperature would be pretty minimal with a tiny amount of compression force through the vertical axis and a small amount of shear through the back step inline with drilled surface.

You’re right too - the bolt hole would need to move out by the thickness of the capping that the step fits into from looking at it now - probably 3mm 

I’ll go and read a bit more about your material suggestions - fantastic ! Thank you so much.

[WesBrooks]

Good morning! Late to the party but this is more my neck of the woods than LRs. Been involved with Rapid Prototyping/Additive Manufacturing/3D Printing for a few weeks off 20 years now.

CAD wise try FreeCAD. It's come on a huge amount in the past 5 years. I think it is a user interface on OpenSCAD and a few other tools. I've been contracting trying to sort someone elses designs out for Additive Manufacture and they wanted me to use Fusion 360. Highly depends on your thought process but I found it a right pain. Yeah, looks pretty but navigating through constraints to find out why your drawing is not fully constrained was next to impossible.

The material extrusion machines are truely very capable for their price point, but quality control on sub £400-500 machines are poor, and some are outright dangerous fire/shock hazards. I've built my own, mostly from existing frames but custom parts from there. That's not necessary but it helps me keep my CAD and design-for-manufacture sharper.

As for running costs if you are just costing material then ectrusion systems can't be beat. However they are slow and not highly reliable, so it is surprising how quickly it becomes cheaper to make something with higher grade commercial powder bed or photopolymer systems.

Personally I want to try some investment casting from printed masters but not found a willing person with kit who is interested in trying it out yet. This could be a great way to get small manifolds and other obsolete  parts made up at low volume.

Here was my small holding shifting some PPE earlier this year:

 

Edited June 19, 2020 by WesBrooks