‘What LatheXXXXX sorry 3D Printer should I buy’

[Neil WyattModerator @neilwyatt]

Posted by Iain Downs on 25/10/2017 18:29:05:

So far the affordable options are all Prusa 3D variants. Are there any other realistic options?

Many, including delta printers, but there's probably a reason why "it is the most used 3D printer in the world."

Neil

[Iain DownsParticipant @iaindowns78295]

Does that make it a Carlsberg product? 'If Carlsberg made 3D Printers ….'

(showing some age here…)

Iain

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Colin LLoyd on 25/10/2017 10:51:43:

Hi Russell, I'm running Mageia 5 64-bit. To be fair, I didn't try very hard as I had a spare laptop sitting around and thought I'd dedicate that to controlling the 3D printer. Subsequently I've found that the printing often comes to a halt if there are more than one USB device plugged into the laptop – typically the USB to the printer and a Memory stick with the STL file on it. But I think this is a MIcrosoft (oh how I hate to say that word) problem where it merrily and randomly changes the USB Communication number. But knowing that – I just copy the STL file to the desktop and remove the memory stick – then no problem. Yes I could convert the laptop to Linux – but I still have some programs that only run on Windows.

I have found that the printer sometimes halts on a long print when running from either Windows or Linux. I suspect the usb signal is getting outside interference in the workshop environment. I now just prepare an SD card using Repetier Host and plug that into the printer to run standalone.

Russell

[Russ BParticipant @russb]

Speaking from experience, Delta printers throw up more challenges for the mind and wallet – for little benefit.

Mainly freeplay/backlash in the Delta arms

Machines that make use of universal joints aren’t very clever.

It’s much harder to accurately calibrate your z axis – since you basically have 3.

Trickyness all round – agile, but tricky…

[Russ BParticipant @russb]

I should add, it’s nothing that can’t be worked/engineered to a satisfying solution – but I don’t think the extra agility or Z height is really worth the hassle!

[Neil WyattModerator @neilwyatt]

To add further comment on Deltas; they go up rather than out, so are good if you are very short of space.

They have round build areas, so may suit 'organic' or 'artistic' subjects like statuettes more than chunky engineered objects.

Neil

[Iain DownsParticipant @iaindowns78295]

There are two others which have popped up on my youtube searches

Creality CR10 which has generally excellent reviews and a very big build area.

Any Cubic I3 again very good reviews, though a 'normal' size.

Both these are pre-assembled (more or less) which is both a benefit and a sadness.

Does anyone have experience with either of these?

Iain

[Neil WyattModerator @neilwyatt]

If the AnyCubic is as good as it looks… it's basically a Prusa i3 witha Mk 8 hot end the same as the Factory 3D but I like the look of the frame (although it does hide bits you may wish to be able to see with a 'skeleton' frame).

Not sure the Creality has a heated bed? If not, avoid.

Neil

[JourneymanParticipant @journeyman]

Neil, I noticed on an image you posted above (now dissapeared) that you have fitted bearings to the top of your Z-axis screwed rods. Is the modified top bracket something you designed or is it available to download somewhere?

John

[Neil WyattModerator @neilwyatt]

Off Thingiverse.

Personally I don't think they don't make a jot of difference in practice, but 9 out of 10 3D printer 'improvements' arre psychological!

Neil

[Colin LLoydParticipant @colinlloyd53450]

Posted by Iain Downs on 25/10/2017 18:29:05:

Thanks all.

On the dual head thing, the main attraction (to me) appears to be to have load bearing and soluble filament so you can easily provide support (soluble) which can be dissolved away after.

Coilin – would that work with the 2 head approach – without a lot of manual processing? If not what benefits does the second head give?

Iain

I bought my Geeetech – not expecting a lot – so went with what the kit had. I was impressed and wanted to try other filaments – so a second head was the cheaper option over a dual-head.

But I suspect the extra mass load on the y-axis rails might eventually be a problem. and I have not investigated what operational considerations you need to take on board within Repetier Host with regard to the different positions of the extrusion nozzles – although I do know you can do "prints" that combine different filaments, either for artistic effect or structural reasons – so I guess Repetier Host manages to cope.

There is also the difficulty of getting the bed to nozzle initial layer printing distance (usually tested and adjusted before each print with thin paper shims to all four corners of the bed) to be the exactly the same for each nozzle – which to my mind seems impossible. Otherwise, when printing with the nozzle that is inevitably slightly higher than the other, the other one will be pressuring the glass plate and, at best, preventing the easy movement of the bed leading to poor builds.

But I'm just surmising here – others with dual head installations have probably solved these issues or don't have problems anyway.

[Neil WyattModerator @neilwyatt]

I'm printing myself a set of 'parallels' at the moment, having screwed up by assuming a step block ground on both sides would be parallel enough for cosmetic work!

I hate using a raft unless I have to, but in this case it means the parallelism of the top and bottom of my prints should be unaffected by any residual bed levelling error.

[Colin LLoydParticipant @colinlloyd53450]

Posted by Iain Downs on 25/10/2017 18:29:05:

Thanks all.

On the dual head thing, the main attraction (to me) appears to be to have load bearing and soluble filament so you can easily provide support (soluble) which can be dissolved away after.

Coilin – would that work with the 2 head approach – without a lot of manual processing? If not what benefits does the second head give?

Interestingly, one conclusion I've come to about what machines you buy (mill, lathe) – old or new, is that if you buy old you need to refurbish it, if you buy new you need to tune it up.

It seems that's true in spades for 3D printers. Unless, I suppose you spend much more (the equivalent of buying a new 'real' lather).

So far the affordable options are all Prusa 3D variants. Are there any other realistic options?

Iain

Sorry Iain – forgot to answer your first point. Yes – the dual head approach will allow the use of soluble support filament to be used. But support can also be achieved at the design stage – as I did for the LED supply box shown above with semicucular tops to the holes. But I could have designed the box with very thin "windows" within rectangular holest – which could then be just pressed or cut out afterwards.

[Colin LLoydParticipant @colinlloyd53450]

One thing I did find I had to adjust with the Geeetech Prusa i3 Printer and I suspect might need the same on similar clones is the "fit" of the Longitudinal bearings on the vertical z-axis. In contrast to the x-axis travel which moves the bed on four shorter longitudinal bearings and uses a toothed belt for movement, the z-axis bearings are 40mm long and any deviation from perfectly straight in the rods causes the bearings to stick especially as the vertical threaded transport rods allow very little accommodation in the bearings. The y-axis transport also has these long bearings but movement is accomplished, again, via a toothed belt and I suspect this more flexible transport has meant I don't have the same problem with the y-axis bearings.

I found that a simple fine emery paper sanding with the rods rotating in the lathe cured the problem. The threaded transport rods maintain the position that any slightly lower contact in the bearings might have compromised. And I see no problems in the resultant prints.

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Colin LLoyd on 26/10/2017 12:21:05:

I found that a simple fine emery paper sanding with the rods rotating in the lathe cured the problem. The threaded transport rods maintain the position that any slightly lower contact in the bearings might have compromised. And I see no problems in the resultant prints.

I did the same. The "smooth rods" supplied were between 7.959 and 8.012 mm. I had to put the biggest one in the lathe and polish it down a bit with very fine abrasive paper to get the bearing to slide smoothly. I had intended to replace them with proper hardened and ground shafting but that was a year ago and the bearings are still running well.

I also fitted ball thrust bearings (ArcEuro ref B8) to the top of the threaded rods to take the weight of the print head off the stepper motors and to allow the flexible couplings to work properly.

Russell

[Colin LLoydParticipant @colinlloyd53450]

Posted by Russell Eberhardt on 26/10/2017 14:26:15:

I also fitted ball thrust bearings (ArcEuro ref B8) to the top of the threaded rods to take the weight of the print head off the stepper motors and to allow the flexible couplings to work properly.

Russell

I noticed that Neil also added these thrust bearings but didn't notice much difference – and he has removed the picture showing them – so if I wanted to add these – how do you do it?

[Neil WyattModerator @neilwyatt]

My bearings are just ordinary radial ones to stop the end of the leadscrews waving about. A typical NEMA 17 stepper is rated for an axial load of 2.5 kg, I don't think thrust bearings will make a noticeable difference?

Go to Thingiverse and search 'prusa i3 z axis ball bearing'.

My printed 'parallels had some high spots that needed scraping off with a scalpel but appear to be parallel to about 0.02mm which is ample for what I wanted.

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Colin LLoyd on 26/10/2017 14:46:20:

Posted by Russell Eberhardt on 26/10/2017 14:26:15:

I also fitted ball thrust bearings (ArcEuro ref B8) to the top of the threaded rods to take the weight of the print head off the stepper motors and to allow the flexible couplings to work properly.

Russell

I noticed that Neil also added these thrust bearings but didn't notice much difference – and he has removed the picture showing them – so if I wanted to add these – how do you do it?

First I extended the threaded rod by turning off the thread for a short length and loctiting a short extension piece in place. That was then skimmed to make sure it was true where it fits into the flexible coupler:

The extended threaded rod was then a good fit in the coupler so it remained co-axial, unlike fitting the threaded rod directly into the coupler when it was off centre.

The bearings were then fitted at the top:

Russell

Edited By Russell Eberhardt on 26/10/2017 15:52:25

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Neil Wyatt on 26/10/2017 15:04:21:

My bearings are just ordinary radial ones to stop the end of the leadscrews waving about. A typical NEMA 17 stepper is rated for an axial load of 2.5 kg, I don't think thrust bearings will make a noticeable difference?

I accept that the steppers are unlikely to wear out in normal use but I found the weight closed up the spiral cut in the couplers and reduced their flexibility. As the threaded rods rotated I could see them moving about and that movement was being transmitted to the printhead. On further thought perhaps the improvement I saw after the modification had more to do with the improved centering of the threaded rod with the better fitting extension?

Russell

[Colin LLoydParticipant @colinlloyd53450]

Posted by Neil Wyatt on 26/10/2017 15:04:21:

My bearings are just ordinary radial ones to stop the end of the leadscrews waving about. A typical NEMA 17 stepper is rated for an axial load of 2.5 kg, I don't think thrust bearings will make a noticeable difference?

Go to Thingiverse and search 'prusa i3 z axis ball bearing'.

My printed 'parallels had some high spots that needed scraping off with a scalpel but appear to be parallel to about 0.02mm which is ample for what I wanted.

Neil – can you post the photo of your version of the bearings for the z-axis threaded rods again. Thingiverse shows many different versions – none of which appears to solve the problem of relieving pressure on the flexible couplings at the base of these threaded rods. I now have the B8 bearings and was just going to drill and tap vertical holes in the top of the threaded rods, then position the bearing on top of the plastic support and then use a bolt and washer to draw the rods up slightly. This seems to me to be the easiest solution to see whether the bearings make any difference rather than a disassemby of the top supports – although that's not a difficult job.

[Neil WyattModerator @neilwyatt]

Mine don't take the weight either.

But any type with 608 bearings, you could run a nylock nut down the all thread until it contacts the bearing inner race.

I have to be honest, applying enough force to influence my universal couplers pulls the frame out of line, which I think is worse.

Neil

[Roderick JenkinsParticipant @roderickjenkins93242]

I've joined the Factory 3D club.

From this:

to this:

In 2 afternoons and an evening.

And, by golly, it works!

That's one of the G code files form the SD card (the Z micro switch holder). Need to sort out the initial adhesion though:

More PVA?

I'm sure I'll find a real use for it . At the moment there are requests for teddy bears and unicorns

Rod

[JourneymanParticipant @journeyman]

Well done Rod, welcome to the club. If you are not already using Cura 3, I can report that it works well with the Factory 3D setup.

John

[Colin LLoydParticipant @colinlloyd53450]

Rod: You quoted – That's one of the G code files form the SD card (the Z micro switch holder). Need to sort out the initial adhesion though:

I use Sainsbury's Basic HairSpray tp provide adhesion to glass plate. Give the glass plate a wipe with Iso-propyl Alcohol and then a light spray with the hairspray. Never had any problems with adhesion – more the opposite -usually need to get a scapel blade under the object to release it. Don't try and release the object until the glass plate has cooled. The other reason for poor adhesion is if the nozzle is too far away from the glass plate for the initial layer. I just go to the 4 corners of the glass plate and then do a Z-axis "Home" with a sheet of normal thin paper beneath the nozzle. If I can pull the sheet out with slight resistance – this seems to work, otherwise adjust the sprung edge bolts on the bed

[JourneymanParticipant @journeyman]

I use diluted (50%) PVA wood glue, works a treat, might have been supplied with the kit. Sometimes it works too well I have pulled bits out of the mirror plate! I have found that if a part doesn't release easily when cold just drop some water on the mirror around the part and it will free up after an hour or so. Worthwhile getting a few spare mirrors (standard size mirror tile) it saves waiting to print the next part.

John

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