3D Printing?

Go for it - the creality fdm are good - just enough quirks to make getting a good print satisfying but without the 5 or 10x price burden to get flawless printing each time.

I would not go for a large bed - 250/300mm print cube volume is more than enough. Larger print beds mean more heating for ABS or PetG filament and print times increase on the cube law.

I use a Prusa I3 mk2 as my daily driver but started on a homebuilt reprap i3 - friend has creality and really no major difference in prints we produce.

I use Fusion 360 as my 3d design software to produce the 3d object from my vision - easier to create engineering object but the guy with the creality is more into sculpture so he used blender.

Filament - ABS is rugged and easy to sand/finish but prone to warping if ambient and bed temps low
PetG easy to print and close to ABS for durability = bit harder to sand/process
PLA easist of all to print but bugger to sand/finish

As always there are ways round all the problems so not hard and fast limitations.

My latest PetG 1 to 1 scale strippable prop weapon project - Sten Mk2

Ross

 

Are you a patient man, with a delicate touch and a mechanical aptitude? I hope so.

My family kindly clubbed together last February and bought me a Creality CR10 V3. Its a nice machine, having a direct drive and a glass bed.

PLA is the easiest material to start with, as it [usually] sticks easier to the bed and [hopefully] flows nicely through the 'hot end' nozzle.

Generally I print direct from Cura slicing software on a Linux laptop, but I think Cura also runs on Mac and Windows.

I soon got bored of downloading other peoples designs from thingiverse. Its much more rewarding designing and printing your own stuff.

Blender looked like too much effort, so I went for FreeCAD which is free and has a good, active forum: FreeCAD Forum - Index page

I have a section on my blog with 3D Printing posts, which may be of interest: Captain Bodgit: 3D printer

If you have a mate with a 3D printer, I suggest you spend a few hours with them and just play...you may get the urge out of your system and save yourself £000s.

Even after buying a machine, a reel of PLA filament is about £25. You wont be happy with just one colour...I think I have 8 reels, so approx £200 worth...it soon adds up!

 

I've supported users with high end Ultimaker printers and one of the significant problems with these is that they need periodic servicing to keep in the plug and play envelope.

As each function degrades the machine compensates so the deviation is invisible to the user giving the appearance of not needing service. When a function get to the point it can no longer self compensate a cascade series of failures happen making everything go to hell in a handcart and a lengthy reset to factory fresh state.

The nearly plug and play devices are much better in my view for the hobby/home user as they are significantly cheaper allowing a taster to see how you want to work and force the user to keep on top of the routine tweaks/maintenance but when things go wrong it is usually a minor fix rather than full strip down.

You expressed a desire to use for widget replication so the fdm is great for this - you can choose the filament material to suit the replication of original part - and have a dimensioned original to create your engineering 3d drawing to 3d object file format (stl/obj/step etc) all in a 3d drafting software of your choice and pocket depth. Plenty of free or open source to get a start and decide what is important to your needs.

Turning the 3d object file into a G-Code text command list is the job of the slicer software - here some printers force you down a linked software/hardware route but again can be replaced with an opensource solution. All that is really important is that you can add and tweak the profile of how your particular printer responds and the characteristics of the filament you are using.

On the whole engineering drawing to G Code work flow - the profile is the only effective tinkering you can do and conversely the answer to repetitive trouble free prints when you get a profile that works and stop tinkering!.

As the printer just reads and actions each line of G Code in sequence my recommendation is to use a method of streaming that is impervious to interruption eg SD or USB Thumbdrive over tethered to a lap top - nothing more infuriating when Microsoft forces an update 3 hours into your 3hr 5 min print! or you fail to disable the sleep function,

As to the finish you can get better standard print with nozzle less that 0.4mm but it needs multiple passes to get the same print height snd this equates to longer print times. For your other hidden agenda (as far as wife/colleague etc) of using the printer to print small highly detailed replicas of technology (not toy tanks honest) the ability to change nozzle diam allows small parts to be printed with higher fidelity and larger parts to sacrifice fidelity for reasonable print time.

It's your design up to you how you split the parts for the build.

Finished article size is not really a restriction I've done from pla rings used in lost wax style metal casting to a 6 foot tall android on the same printer.

Gallery V2 – InMoov

Ross

 

If tanks are your thing, I'm sure you will find plenty of oven-ready designs that you can download and simply print from the provided .stl files: Tanks: A Collection by glitchpudding

However, it you want to be creative, but have little or no experience with 3D CAD, my suggestion is that you download suitable software and get-stuck-in before you spend any money on a printer. I'd had 2D experience, but still found it a hard slog to understand and do anything useful on 3D. But now that we have long dark nights and the garden has [almost] gone to sleep, its a bit easier to find some time for desktop work!

I agree with Ross about the potential dangers of printing via a connected computer. In my case I'm all Linux, so no unexpected surprises from updates, or screen & power savers. Windows users seem to report problems finding/enabling com ports and downloading drivers for the serial ports typically found on 3D printers...no such problems on Linux, it just works.

If I was trying to do an over-night print, or one that would take more than (say) 8 hours, I'd load the g-code file onto the printer's SD card and print from there. But for anything else, I just manage the print from an old dedicated laptop, while avoiding running most other programs (especially the 3D design software).

I mentioned that PLA was [probably] the easiest filament to work with, but remember that this is a rather brittle, biodegradable plastic (I've got a PLA printed name tag hanging on a rose bush as a test, to see what happens after spending 12 months outside). With this in mind, you may need to use something else (maybe ABS) for safety-critical components like bog seats!

One other basic thing to point out is that with a single extruder printer, you can only print one colour at a time. As the printer prints layer-by-layer, there is usually (on my machine at least) the option to reload filament and thereby print different layers using different colours: Captain Bodgit: Multicolour printing on Creality CR-10-V3 with Cura
But if you wanted to print (say) a chess board in one piece, you would need a dual extruder printer.

I hope some of this nonsense helps.

 

Just a couple more points, then I'll go away.

Did I mention the mess? I find very fine threads of PLA on the carpet in my man cave. The Dyson is not great at picking them up, as they offer very little wind resistance, but they stick real nice to the carpet.

I maintain that the winter is the best time to use a 3D in my house. This is because the central heating holds the room temperature and relative humidity within narrow limits. I have bigger printing problems in the summer, when the temperature might be 16'C in the evening, then 30'C during the day, and the RH is often well above 50%, frequently in the 80s & 90s (the filament absorbs moisture and all hell breaks lose!)

 

Welcome to the dark side of the force!

Got the 1:1 Sten for you to print when you get up to speed .

Ross

 

It's character building honest!

That first layer or two is the foundation for overcoming print abuse later.

I use a brim to give me the best chance for 1st layer adhesion - IPA (Iso - not India) print surface cleaning gets rid of the greasy finger prints that I cannot see but printer does

 

How to Calibrate the Z-Offset on the E2 3D Printer

Good guide - For my first prints I was so intent on getting the first layer smeared over the print bed that it had so little height that the next layer failed to bond to it.

Had to put trust into bed levelling and z offset to get prints that adhered on first and second layers.

Try just printing a just a square (say 2cm x 2cm) 1mm height. to dial in before trying a full model.

If the first layer does not look like the uniform goldylocks middle picture. Cancel the print, clean, check bed levelling and try again. with Z offset changed by +/-0.1mm (crude steps at first to get you into the area of setting then try steps around that of 0.05mm. On my prusa with nozzle clearance set cold to just drag on a sheet of paper pulled between bed and nozzle i need a z offset of around -0.650 to -0.730.

Ross

 

Great stuff - the magnetic plates have a bit of wave in them after a few print cycles but in practice this has a limited effect.

I clean with IPA before each print and used to do a wipe over with Acetone every dozen prints or so as the IPA was great for grease/duct etc but over time there was a build up of filament that I could never see but it was just enough to allow prints on settings that previously worked to fail. Now I IPA clean until prints start to lift and then do an Acetone followed by IPA maintenance surface wipe.

Get into the repeatible ball park for first layer sticking and rather than tweak Z by small increments try tweaking the nozzle temp by 5 deg or so.

Different manufacturers filament operates at slightly different temps to that on the standard profile. Too high temp and it flows well but does not form the bead that you need and stays soft too long. Too low a nozzle temp and it curls back on itself rather than adhering to the previous.

Like flying a helicopter - little changes to first layer bed temp, nozzle temp and z height all together rather than try to set one then move onto the next.

I use profile for bed temp, filament manufact recom for nozzle and rough initial setting for z height that worked before. tweak bed temp and nozzle temp up and down together to get what works.

Older filament can absorb atmos moisture so I expect to tweak nozzle temp periodically over the time that I use a spool.

A Benchy boat test print is great for fine tuning the printer for a new filament manufacturer moving forward.

Ross

 

As someone who grew up on drawing board, then went to autocad 2D, autocad/turbocad 3d, all the money grabbing Autodesk products, sketchup, freecad and 3D virutal/augmented reality model stream production such as blender, etc I now teach "Stem" to youth groups and grad levels.

I can confidently say - no one CAD package is better or worse than another - the trigger is how much you need to bend your current favourite to do the new task.

For the Stem teaching, and my own first grab I use Fusion 360 - its free for hobbist https://www.autodesk.com/products/fusion-360/blog/changes-to-fusion-360-for-personal-use/ but for the main reason is that it works on primitive 3d shapes rather forcing me to CAD a 2d then loft.

By that I mean that I think in 3d and draw by adding or subtracting standard shapes such as cube, sphere, cone etc.

Take the Sten Barrel - first select a cylinder primitive - set diam and height.

On the top face, on centre of cylinder draw a circle plane for the od of the metal barrel.
Using the same centre draw the circle plane ID of the cooling shroud to leave 5mm thickness on the overall cylinder and another one for its OD around the metal barrel hole circle plane to give say 5mm thickness round the od of the metal barrel.

Now select the circle face of the barrel from centre to barrel od - push this through the entire length of the cylinder primitive to subtract and create a through hole. Then select the surface between the cooling shroud ID and OD. Push this part way through the cylinder primitive to subtract a hole that stop say 10mm short of going all the way through.

Cooling holes are done the same way select a reference plane - draw the number of circles you want then select them and drag up and through the remaining thin side wall of the cooling shroud.

No real CAD involved to create the 3d shape just a combination of primitives and shapes that you push/pull to add/subtract from the original primitives.

Takes longer to explain that to actually do the model! That's why I prefer it to 2d and loft. You can do this in Fusion360 as either traditional part creation or in combination with primitives - just that for the most part you do the task by primitive shape manipulation like clay modelling rather than engineering.

R

 

Me too!

I even gargle a glass or two.