Prusa i3 3d printer

[ge_rik]

Does anyone have any inside knowledge on these 3d printers?
https://www.ebay.co.uk/itm/123992812522

At £80 it seems like incredibly good value or is it a case of you get what you pay for?

Incidentally, when I looked at them last week they were £70!

The powers that be has given me permission to fork out the readies, but I just thought I'd check here first.

Rik

[metalmuncher]

While I don't have any experience with that specific printer, my printer was an relatively inexpensive i3 clone built from a kit, but a more traditional design with threaded rods and aluminium frame without bracing.

I've found with a cheap printer you are not buying a printer, you are buying a project in itself. I bought my printer just under 5 years ago, and just in the last year have I started to consider the machine a tool to get things done reliably. It's been through numerous rebuilds and upgrades over the years, and I'm now at the point where I want to look at completely different printer designs to get more performance.

Of course, all of the above is fine if you actually want a new project, and overall I have enjoyed working on the printer even if it has been a source of frustration at times, but if you want a reliable workhorse from the get-go I'd buy something else, like a prebuilt genuine Prusa machine - downside being 10x the cost.

Now, £80 for all those components actually seems like pretty good value, I think you would struggle to buy just the motors and linear axis components for £80 separately, but as I described above I would prepare to fork out a lot more than just that to achieve nice prints. A nice genuine E3D hotend can cost £50 on its own if you feel the need to upgrade that for example.

[ge_rik]

Well, it looks like it's going to be delivered on Thurs or Fri. In the meantime, could those who know recommend some 3d drawing software which might be suitable, preferably free or cheap? I'd like to get my head around it asap so I can hit the ground running when the printer arrives.

Rik

[philipy]

I'v always used Sketchup Make 2016, which is free but no longer supported since they tried to force users to go 'in the cloud'.
There is also SU Make 2017 but I had problems with that because of incompatibilities with the graphics card ( it requires a separate rather an on-board card) but 2016 is perfectly adequate for what we need. Download at http://dl.trimble.com/sketchup/2016/en/ ... en-x64.exe
Don't know if you've ever used a 2d CAD program, but 3D is completely different and it did take me a while to mentally dump AutoCad LT which I used at work back in the day!
There are loads of videos on Youtube and 4 ( I think) basic getting started video's on the SU site, just google what you want.

If I can help with anything specific, PM me or you've got my email .

I know a lot of people talk about using Fusion which is an Autocad 3D program but I found it incredibly complicated, like all AutoCad stuff and I think I'm sticking to what I know - old dog, new tricks...!

[metalmuncher]

I would second Sketchup as a first program for 3D modelling. It has many limitations compared to a parametric CAD program but it is quite easy to use, it was the first 3d modelling software I used.

I now use Fusion 360 as my main CAD tool for 3D printing. Yes, it is more difficult to get into, but it is significantly more powerful, honestly I am surprised Autodesk still allow hobbyists and small companies to use it for free, it is incredibly feature rich. The main advantage in modelling over Sketchup is that it is parametric and keeps a history of your actions. This can be extremely useful for making quick modifications to your model. Let's say you have modelled your chassis, but decided you want to change the wheelbase. You can go back in time to when you defined the hole spacing for your axles, alter the wheelbase, then replay the actions you did after that, the program automatically updating your wheel positions, cranks, connecting rod length, motor position & its mounting holes, etc. Admittedly, for all that to work it depends on you telling the program what relationships you want between those components and therein lies the complexity.

A program I have played with in the past is SolveSpace. It works in a more similar way to parametric CAD programs like Fusion or Solidworks, but is nowhere near as daunting as Fusion, might be a good intermediate skill program.

If you have some programming experience there is OpenSCAD, which is also parametric but works in a very different way to most other CAD programs. And then there's Blender, which is useful for modelling more natural objects that are hard to do in CAD - people, animals, rocks, etc. Like Fusion, this is extremely powerful software, but it has probably one of the worst learning curves of any software I've seen.

[ge_rik]

Thanks chaps. Plenty of food for thought here. I'll start off with SketchUp, I think. Sounds like the least daunting route into this new territory.

Thanks for the offer of brain-picking, Philip. I'll no doubt need to take you up on it.

Rik

[SVLR]

We have a couple of genuine Prusa i3 mk3s in school they are awesome machines and running 24/7 at the moment producing PPE visor frames for key workers.

I would say use Fusion 360 by Autodesk, beats Sketchup hands down in my opinion, and fairly easy to pick up. In my opinion its a no brainer, really powerful 3D modeller with built-in slicing software to talk to the printer or a really easy STL generator to make the file needed for the slicer program. I have made lots for the garden railway - quarry tubs, door handles, brake pipes, coach steps, buffers (see pic below) coach vents, pot-bellied stove and many more bits and bobs.

buffer with hook v6 by Jonathan Demery, on Flickr

[SVLR]

Scratch built coach almost finished, it uses 3D printed buffers, door handles and suspension details, need to add the roof vents, steps and brake pipes which were also 3D printed.
20190127_160504 by Jonathan Demery, on Flickr

[philipy]

Those buffers etc are most impressive, no doubt about that, but I can't agree that Fusion 360 is easy to pick up. I've made a couple of attempts and got absolutely nowhere. I simply can't get my head around how to do it.

[SVLR]

Those buffers etc are most impressive, no doubt about that, but I can't agree that Fusion 360 is easy to pick up. I've made a couple of attempts and got absolutely nowhere. I simply can't get my head around how to do it.

We use it in school with 11 to 16 year olds (the sixth form use Inventor) most of them pick it up really easily, if you can use sketchup you will pick up F360 really quickly just start with simple stuff first.

[Jimmyb]

Those buffers etc are most impressive, no doubt about that, but I can't agree that Fusion 360 is easy to pick up. I've made a couple of attempts and got absolutely nowhere. I simply can't get my head around how to do it.

We use it in school with 11 to 16 year olds (the sixth form use Inventor) most of them pick it up really easily, if you can use sketchup you will pick up F360 really quickly just start with simple stuff first.

I don't doubt 11 - 16 years can pick it up, but I know 50 somethings that can't set up the "old" TV programme recorded, I believe the phrase is "horses for courses"

[tom_tom_go]

I have worked with people well into their 60s that are far more clued up with IT than people half their age.

Age is irrelevant, life experiences is what counts...

[ge_rik]

OK. It's taken a few days, but I feel I'm beginning to have something to show for my labours. The structure of the printer is now more or less complete - at least it does sort of look like a 3D printer!

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It's certainly been an adventure to get this far.

The next stage is to add the electrics and electronics and then wire everything up. And then, of course, I'll find out if it actually works!!!

Rik

[tom_tom_go]

Hope it works out Rik.

I am still not sold on 3D printing for garden railways as you don't get a clean finish after printing and people seem to have to spend a lot of effort to achieve a finish that is not on par of what a resin moulded part would give you.

[Peter Butler]

I am still not sold on 3D printing for garden railways as you don't get a clean finish after printing and people seem to have to spend a lot of effort to achieve a finish that is not on par of what a resin moulded part would give you.

You really think so?....

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[metalmuncher]

I am still not sold on 3D printing for garden railways as you don't get a clean finish after printing and people seem to have to spend a lot of effort to achieve a finish that is not on par of what a resin moulded part would give you.

You really think so?....

While the finish on that is very nice, he has got a point that you need to put a lot of effort in to get a result like that.

I used to (naively) hope that 3D printing would save on effort when producing models, but there really is no substitute for putting in the work to get a nice model. I made the Hudswell Clarke BE loco as an experiment in making something quick with minimal 'manual' input, printing fully pre-detailed parts, sanding only where necessary for fit, gluing the components together and quickly dusting over with a rattle can. It looks pretty nice and densley detailed from a distance, but the finish breaks down when close up.

You can either print the components and spend most of your time fettling to get a nice finish, or you can spend most of your time making the components out of plasticard or wood and less time getting a nice finish. I think the best way is somewhere in the middle. If I were to build the Hudswell Clarke again with the goal of getting a better finish, I would probably build the major components from sheet stock, and use printed parts for the details like axleboxes, springs, etc. Small detailing parts are the best use of printing for model railways in my opinion - being able to knock off 4 identical leaf springs or 10 buffers at once is much less effort than making the same quantity by hand, and the printing defects can get hidden in the details.

Good luck with the rest of the build Rik, it will be interesting to see what £80 in components can achieve.

[ge_rik]

....... Small detailing parts are the best use of printing for model railways in my opinion - being able to knock off 4 identical leaf springs or 10 buffers at once is much less effort than making the same quantity by hand, and the printing defects can get hidden in the details.

Good luck with the rest of the build Rik, it will be interesting to see what £80 in components can achieve.

That's my thinking. I didn't fancy the prospect of making 14 identical bus seats by hand. I could have made one and then used it to make a mould for resin casting, but wondered whether 3D printing might be a quicker process (not counting the time spent constructing the printer).

I'll have to get to grips with the 3D drawing software but I have found an online source for a 3D drawing of bus seats if the drawing process defeats me.

My cheapo printer might produce fairly rough and ready printouts, but as the seats will be tucked away inside I might be able to get away with it.

Rik

[philipy]

We've had discussions about finish, size of pieces, suitability, etc in the past and basically from my own experiences I'd agree that smallish components work best. As I've said before, I tried printing a complete van, which was a disaster but adding printed detail to a styrene box worked well.

Having said all that, these days 3D printers are used commecially for all sorts of medical and fairly high precision engineering jobs, but then again they would probably add at least 3 and possibly 4 noughts to Rik's £80. I know it is said that a bad workman blames his tools but then again you only get what you pay for.

[ge_rik]

Having said all that, these days 3D printers are used commecially for all sorts of medical and fairly high precision engineering jobs, but then again they would probably add at least 3 and possibly 4 noughts to Rik's £80. I know it is said that a bad workman blames his tools but then again you only get what you pay for.

I'll not try printing myself a new heart valve just yet then .....

Rik

[ge_rik]

OK - the printer is now up and running .....

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Sorry it's a bit blurry, it was getting late last night when I took this.

My first print out wasn't entirely successful ...

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A barrel, downloaded off the web for free. 2/3 of the way through printing it, one of the vertical guide rods became detached (partly poor design and partly because I hadn't tightened the restraining screw enough). However, as you can see the striations are fairly prominent. I'm not sure if this is because of the quality of the printer, the quality of the drawing or there are some settings which I can adjust to improve matters. I did increase the size from the original drawing, whether that makes a difference to the quality? Any suggestions?

My second model is a bit more successful - a pigeon basket which was often seen on rural platforms between the Wars.

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As it's wickerwork, the striations don't really matter. This was actually reduced in size from the original and maybe that helps?

Anyway - it seems to work. I've ordered more filament as I've nearly run out of the small reel they sent with the printer. My next job is to get to grips with Sketchup to make a drawing of the seats for the railcar .....

Interesting times.....

Rik