• The Plug Track functions are experimental and still being developed. Some of the earlier pages of this topic are now out-of-date.

    For an updated overview of this project see this post.   For some practical modelling aspects of using Plug Track see The Book of Plug Track.

    Some pages of this and other topics include contributions from members who are creating and posting their own CAD designs for 3D printing and laser-cutting. Do not confuse them with Templot's own exported CAD files.

3D FDM Printers!

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Paul Boyd

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Gosh, this grew whilst I wasn't watching! At the moment, I feel very nervous about deviating from Cura's default settings too much, so until I get a much better understanding of exactly what does what I won't be that adventurous! For instance, right now I'm not even sure if changing the nozzle setting is a permanent preference (at least, until it's changed again) or if it's part of the gcode or saved in the project file, and then how do I know which nozzle I intended for a given file if I want to print it years later? To which Martin's answer will be "stick with 0.4mm and adjust the flow in the slicer". It's that "a lot of calculation of the settings" bit though that's not good - maths has never been a strong point of mine!

My current thoughts, and part of the reason for buying the printer, is that printing a set of timber frets would suit my preferred method track building nicely, but then get the chairs printed elsewhere. Having said that, I know I won't be able to resist having a go at printing chairs with the 0.2m nozzle, not in the expectation that they'll be usable but just to see what results are. I learn much better by actually trying things out. That means I need to hook the printer up to the PC at some point to do lots of little test prints without the faff of using a memory card, which means I somehow need to get the PC and printer near enough to each other :confused:

I'm still focused on learning FreeCAD, in between other non-modelling projects. RMEUK sell rather nice 3D printed board mounts for the various MERG CANMIO boards, but not for any of the other MERG boards (yet?) and most definitely not for my own boards! Those will be my next design goal, for which a 0.4mm nozzle or even bigger will be fine.

Cheers,
Paul
 
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I feel very nervous about deviating from Cura's default settings too much, so until I get a much better understanding of exactly what does what I won't be that adventurous! ...

My current thoughts, and part of the reason for buying the printer, is that printing a set of timber frets would suit my preferred method track building nicely, but then get the chairs printed elsewhere. Having said that, I know I won't be able to resist having a go at printing chairs with the 0.2m nozzle, not in the expectation that they'll be usable but just to see what results are.
@Paul Boyd

Hi Paul,

There's a Settings Guide for Cura, which for some reason has to be installed as a plug-in. Then hovering over any setting displays a detailed explanation:

cura_settings_guide.png


You can also get the same info by right-clicking on a setting and then Settings Guide on the menu which appears. The info then appears in its own window in a much more readable font.

With so many settings this is easier to find than navigating through the web pages:

https://support.ultimaker.com/hc/en-us/articles/360012512340-Wall-settings

To get the plug-in, click Marketplace button top-right, then the Plugins tab. There are dozens of plugins to choose from if you scroll down (no obvious scrollbar until you roll the mouse!). One I find essential on the BIBO is right at the bottom, ZOffsetSetting, to adjust the height of the finished model to match what you intended it to be.

Despite playing about with a CNC miller, I still think the FDM-printed timbering bricks will be the default system for Plug Track, and more likely to suit the equipment Templot users have available.

In 7mm scale I FDM-printed these chairs using an (actual) 0.2mm nozzle:

2_252112_540000000.jpg


2_252113_340000000.jpg


in standard PLA instead of the toughened PLA PLUS which I used for the timbers. The choice of polymer can make a big difference.

As far as I remember that was done using Slic3r (free) instead of Cura.

More info: https://85a.uk/templot/archive/topics/topic_3307.php#p26444

But my FDM experiments in 4mm scale produced dismal results, I suspect resin-printing is the only sensible way for detailed chairs in 4mm scale -- short of having your own injection-moulding machine. :)

cheers,

Martin.
 
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Paul Boyd

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@Paul Boyd

Hi Paul,

There's a Settings Guide for Cura, which for some reason has to be installed as a plug-in. Then hovering over any setting displays a detailed explanation:

View attachment 2302

With so many settings this is easier to find than navigating through the web pages:

https://support.ultimaker.com/hc/en-us/articles/360012512340-Wall-settings

To get the plug-in, click Marketplace button top-right, then the Plugins tab. There are dozens of plugins to choose from if you scroll down (no obvious scrollbar until you roll the mouse!). One I find essential on the BIBO is right at the bottom, ZOffsetSetting, to adjust the height of the finished model to match what you intended it to be.

Despite playing about with a CNC miller, I still think the FDM-printed timbering bricks will be the default system for Plug Track, and more likely to suit the equipment Templot users have available.

In 7mm scale I FDM-printed these chairs using an (actual) 0.2mm nozzle:

2_252112_540000000.jpg


2_252113_340000000.jpg


in standard PLA instead of the toughened PLA PLUS which I used for the timbers. The choice of polymer can make a big difference.

As far as I remember that was done using Slic3r (free) instead of Cura.

More info: https://85a.uk/templot/archive/topics/topic_3307.php#p26444

But my FDM experiments in 4mm scale produced dismal results, I suspect resin-printing is the only sensible way for detailed chairs in 4mm scale.

cheers,

Martin.
Hi Martin

Thanks very much for pointing me at that plug-in - it looks incredibly useful! Even just that screenshot you showed talking about line widths is more than I found elsewhere, so that plug-in will be installed this evening.

I think I still need to work on my employer to get a resin printing setup though!

Cheers,
Paul
 
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Even just that screenshot you showed talking about line widths is more than I found elsewhere, so that plug-in will be installed this evening.
@Paul Boyd

p.s. Paul,

You can also get the same info by right-clicking on a setting and then Settings Guide on the menu which appears. The info then appears in its own window in a much more readable font. I've only just discovered that. :)

cheers,

Martin.
 
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Martin Wynne

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@Paul Boyd

p.p.s. the Settings Guide includes a useful Glossary of 3D printing terminology:

cura_settings_guide_gloss.png


Martin.
 
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Paul Boyd

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Good evening!

Tonight's shenanigans! Although the 0.2mm nozzle arrived today, it's still firmly sealed in its bag - I need to get used to what I've got first, I think.

I've installed the Settings Guide and FreeCAD plugins - the former in particular is brilliant so thanks for pointing me at that, Martin. I also found a Cura plugin for FreeCAD, so the other way around.

I've been using the gears shown earlier to experiment with settings, and had a few cancelled prints this evening. The ones in the photo below aren't at all bad, although not visible in the photo is that one of the gears suffered from poor adhesion to the bed in one spot so some filament got picked up and turned into a blob. These were printed with the 0.4mm nozzle, with a line width of 0.3mm and a layer height of 0.15mm. Speed was 45mm/s. They're still stuck to the bed although I've removed the surrounding skirt.

2021-09-24_20-53-54_IMG_0171.jpg


Apart from the aforementioned blob, these look like they might actually be usable, and have a much better shape than my first attempt the other day using Cura's default settings.

The other change was to mount the printer on a spare Ikea shelf which in turn was mounted on four Oehlbach dampers. I was very pleased that that virtually eliminated the vibrations into the flat - I could no longer feel the printer through my chair a few metres away!

2021-09-24_20-32-16_IMG_0168.jpg

The hotend fan though - that really does need to change! All the fans really have a very irritating variety of white noise, mostly air swirling around flat metal plates instead of neat wire mesh guards. I have some ideas there.

The other problem I had this evening was a warped bed. A lot of googling and fiddling followed, and it essentially came down to the four point levelling creating a bow in one direction - one diagonal pair was at a slightly different level to the other. I spent more time this evening sorting that out and got the bed nice and flat, and level. Now I understand why it's so important to spend that time not just levelling the corners but also the centre.

This faffing about with memory cards really is a pain. Having looked up USB 2 specs, I found that the maximum length allowed is 5m, so a 5m cable is on order. That'll make experimenting much easier, although I think for real prints, especially bigger ones, I'll stick with the memory card.

One thing I'm a bit puzzled about is that when I withdraw the filament by following the instructions precisely (either method!), the guide on the filament drive has to be pulled out with it because the end of the filament is now too large a diameter to come through the hole. I then need to cut the last inch of filament off to remove the guide so I can refit it. I'm sure that's not right!

Anyway, I hadn't planned to do any of this tonight!

Cheers,
Paul
 
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AndyB

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@AndyB

Hi Andy,

Please feel free to contradict me as often as you like. :)

I use only one nozzle on the BIBO now. The dual extruder function was a big disappointment and can only work if you get the two nozzles exactly level with each other. For which no means of adjustment is provided, without taking the entire extruder head to bits. So changing either of the nozzles is a day's work. I've removed the second nozzle and I'm keeping the seconder extruder in reserve in case of any problems with the first one.

It's currently fitted with a 0.6mm nozzle which means I can make non-detailed things, such as the filing jigs, much faster.

But it can also do finer detail work if I fiddle about with the settings and G code. For example, this attempt to create code 75 bullhead rail in PLA PLUS was made all using the 0.6mm nozzle:

2_111752_390000002.jpg


2_111752_390000000.jpg


The rail foot was made using a single wall 0.9mm wide by over-extruding from the 0.6mm nozzle. The rail web only 0.4mm wide was made by under-extruding from the same 0.6mm nozzle as a single wall. For the rail head and important top corner radius I fiddled about with multiple passes from the same 0.6mm nozzle with various different rates of under-extrusion. It took a lot of trial and error to get the results above, but it was all quite repeatable once set up. I could even get down to near-scale 0.3mm web, again using the 0.6mm nozzle, but the result was too fragile. The rail can be printed straight or curved to any radius, but is quite flexible if needed. The major drawback is the limited rail length of 200mm on the BIBO build plate, so can do only prototypes of 45ft rails in 4mm scale. When I've got the Plug Track done I want to get back to it, for battery/radio control, but more practically in 7mm scale.

For anyone using a standard 0.4mm nozzle, I think you could get down to 0.2mm details using the same under-extrusion method.

cheers,

Martin.

Actually I think that's a load of complete and utter baloney :giggle:

But I might change my mind if you can reproduce the 00 BH chairs I produced on my printer with a 0.2 mm nozzle.

Is that sufficient contradiction?
 
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Martin Wynne

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@Paul Boyd

Hi Paul,

I noticed on your gears you have some "elephant's foot" on the gears where the first layer has squidged out sideways on the heated bed:

paul_gear.jpg


On many jobs that doesn't matter (timbering bricks?), and you can improve the adhesion by squidging more firmly against the bed by having the nozzle closer to the bed than designed (use the Z offset plugin) or by increasing the flow rate on the first layer.

But it's not something you would want on the teeth of a gear wheel. There's a setting in Cura to fix that. Set a negative value for the first layer expansion:

cura_initial_layer.png


p.s. I don't recognise your bed material -- on the BIBO it's a glass plate. Is that a magnetic sheet? Does it work well?

cheers,

Martin.
 
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Paul Boyd

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@Paul Boyd

Hi Paul,

I noticed on your gears you have some "elephant's foot" on the gears where the first layer has squidged out sideways on the heated bed:

View attachment 2317

On many jobs that doesn't matter (timbering bricks?), and you can improve the adhesion by squidging more firmly against the bed by having the nozzle closer to the bed than designed (use the Z offset plugin) or by increasing the flow rate on the first layer.

But it's not something you would want on the teeth of a gear wheel. There's a setting in Cura to fix that. Set a negative value for the first layer expansion:

View attachment 2318

p.s. I don't recognise your bed material -- on the BIBO it's a glass plate. Is that a magnetic sheet? Does it work well?

cheers,

Martin.
Hi Martin

Ah, "elephant's foot" - is that what it's called? I had noticed that but hadn't got around to trying to work out how to stop it, or even what to google! Thanks for the tip - I'll give that a go shortly. I seem to be using these gears for experimenting, but in fact I won't use them in real life as they're about 1:3 whereas I'd prefer 1:2.

The bed is glass with some sort of coating to help with adhesion. It seems to work ok!

Cheers,
Paul
 
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Paul Boyd

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A bit more progress this afternoon, and I think this is about as good as I'm going to get. Further playing was just going backwards. There's still a little bit of 'elephant foot', but it seems to be contained within the overall profile, or as near as makes no difference!

2021-09-26_16-49-44_IMG_0179.jpg
The Initial Layer Horizontal Expansion of -0.2 just lost the teeth entirely, but -0.05 worked ok. I also used a Z offset of 0.02mm which also helped, although I guess that figure will need to be adjusted every time I level the bed (which I hope won't be that often). Bed temperature was reduced from 60 to 50 deg, and nozzle temperature from 210 to 200. I also reduced the wall thickness to 0.6mm although that didn't seem to make much difference to the tooth profile - I hoped it would.

There were a few rejects along the way! I also had to contend with a partially blocked nozzle so the filament was curling out instead of dropping straight down, and I also found I needed to clean the bed a little more often than I had been for good adhesion, particularly as the settings tended towards reducing adhesion anyway. I might have a play with rafts another time, and see how that goes.

2021-09-26_16-50-12_IMG_0180.jpg

I've also found a plugin to allow all the settings to be exported as an HTML file which will be very handy. I've attached the PDF version of the setting used for the gears in the attached photo.

Cheers,
Paul
 

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Martin Wynne

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@Paul Boyd

Hi Paul,

Lots of gears! :)

Is that ordinary PLA? I think you could try lower than 200 degrees. I generally use 190-195 for the main part of a print. But it does depend on the relative accuracy of our thermistors.

Thanks for the PDF.

For something like gear teeth, where the accuracy of the outer profile is important, you might try these two settings:

Infill Before Walls

Outer Before Inner Walls


Either one or the other, or both at once.

cheers,

Martin.
 
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Paul Boyd

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@Paul Boyd

Hi Paul,

Lots of gears! :)

Is that ordinary PLA? I think you could try lower than 200 degrees. I generally use 190-195 for the main part of a print. But it does depend on the relative accuracy of our thermistors.

Thanks for the PDF.

For something like gear teeth, where the accuracy of the outer profile is important, you might try these two settings:

Infill Before Walls

Outer Before Inner Walls


Either one or the other, or both at once.

cheers,

Martin.
Hi Martin

Lots of gears, none of which I'll use! They make a good exercise piece though.

As far as I know it's ordinary PLA, Anycubic branded. In fact, the box suggest 190 to 230 degrees so there's scope for going lower. All the digging I've done suggests elephant foot is usually temperature related, so that initial layer hasn't cooled enough and gets squidged by subsequent layers if I'm understanding it correctly. It can also be caused by bed warp, but I'm very sure now that the bed is very flat.

I had find those wall settings and read the Settings Guide description which goes into the pros and cons. I've sort of got that next on my list to try, but I really want to get into designing my own stuff, in between scanning hundreds (actually, 1000s!) of negatives!

Cheers,
Paul
 
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@Paul Boyd

Hi Paul,

A couple of downsides to Cura 5:

1. the Settings Guide plug-in doesn't work. Although quite a lot of it seems now to be built in.

2. more significantly, Cura 5 won't load existing gcode files for preview. Even its own saved gcode files it reports as corrupt and unloadable, all of 10 seconds after saving them. I assume this is a bug and will get fixed. I was having to go back to Cura 4 to preview old gcode files.

But the good news is Prusa! I haven't used the slicer, but Ive discovered it comes with a separate stand-alone gcode viewer and simulator, which is excellent:

prusa-gcodeviewer.exe

I've created a separate desktop shortcut for it.

prusa_gcode_viewer.png


Drag the sliders or use the arrow keys to simulate printing. Lots of options and settings to try.

Naturally as with any software there is at least one annoyance -- Cura numbers the layers starting from 0, Prusa numbers the layers starting from 1. So if cross-checking (from the comment lines in the code) you can easily get confused by forgetting to add or subtract 1. Or in my case 2, because Prusa counts my pre-print nozzle-purging code as a separate layer.

Included in the slicer download:

https://www.prusa3d.com/page/prusaslicer_424/

cheers,

Martin.
 
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Paul Boyd

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@Martin Wynne

Hi Martin

1. the Settings Guide plug-in doesn't work. Although quite a lot of it seems now to be built in.

Ah, yes, I did spot that!

2. more significantly, Cura 5 won't load existing gcode files for preview. Even its own saved gcode files

Hmm... In 5.1.0, I've just opened gcode generated by Cura 5 Beta and it's fine, as is gcode generated by Cura 4.something. That generated by PrusaSlicer opened, but showed the whole model as one layer. At no time did it complain that any file was corrupt.

But the good news is Prusa! I haven't used the slicer, but I've discovered it comes with a separate stand-alone gcode viewer and simulator

It does indeed, and very useful that is too! I really do like PrusaSlicer, but not having a hole size expansion function is a pain. Output is very good, but I think Cura 5 is better.

Cura numbers the layers starting from 0, Prusa numbers the layers starting from 1. So if cross-checking (from the comment lines in the code) you can easily get confused by forgetting to add or subtract 1. Or in my case 2, because Prusa counts my pre-print nozzle-purging code as a separate layer.

OctoPrint also seems to add 1 to the layer number, so altogether it can a bit confusing. I must admit that apart from start and end code (which reminds me that I haven't set that on the new install) I haven't really looked at the gcode.

Cheers,
Paul
 
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Martin Wynne

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Hmm... In 5.1.0, I've just opened gcode generated by Cura 5 Beta and it's fine, as is gcode generated by Cura 4.something. That generated by PrusaSlicer opened, but showed the whole model as one layer. At no time did it complain that any file was corrupt.
@Paul Boyd

Hi Paul,

Very odd. :confused:

No way will my Cura 5.1.0 on Windows10 load any existing gcode file for viewing.

Until that is, I edit the file to use Unix line endings (LF) instead of Windows (CR/LF). After which, hey presto, it works fine!

I had a similar problem with the gcode files for my CNC miller. Perhaps they are both using the same Marlin gcode interpreter?

Possibly it's related to Windows10, and you are on Windows11?

But Cura 4 works fine regardless.

Just one more thing to remember, or more likely forget. I think I shall be sticking with the Prusa gcode viewer.

cheers,

Martin.
 
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Paul Boyd

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@Paul Boyd

Hi Paul,

Very odd. :confused:

No way will my Cura 5.1.0 on Windows10 load any existing gcode file for viewing.

Until that is, I edit the file to use Unix line endings (LF) instead of Windows (CR/LF). After which, hey presto, it works fine!

I had a similar problem with the gcode files for my CNC miller. Perhaps they are both using the same Marlin gcode interpreter?

Possibly it's related to Windows10, and you are on Windows11?

But Cura 4 works fine regardless.

Just one more thing to remember, or more likely forget. I think I shall be sticking with the Prusa gcode viewer.

cheers,

Martin.
Hi Martin,

Odd indeed - I’ve just run the same test on my old Win10 PC, albeit with Cura 5.0.0, and get the same results as with Win11.

However, in real life I don’t think I’ve ever loaded gcode into Cura, much preferring Prusa’s gcode viewer. Which means I’d better put that onto the new PC!

Cheers,
Paul
 
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@Paul Boyd

Hi Paul,

I've been doing battle with Cura 5 on my new Neptune 2S.

The problem for a long time has been the width of the sockets in plain sleepers in 4mm scale. The plugs are 2mm wide, plain track sleepers are 3.33mm wide. That means the wall each side of a socket needs to be about 0.6mm thick, or a bit more. That's a problem using a 0.4mm nozzle.

Using a narrower plug on the chair isn't an option -- it wouldn't be wide enough to contain the slot for the loose jaw pins, and the delicate thin chair base surrounding it would be wider than is good for reliable resin printing. It would also make CNC-milling the sockets more difficult.

So the choice is to do a single wall and over-extrude from 0.4mm in the hope of creating a thicker wall; or do two walls and under-extrude in the hope of creating a thinner combined wall.

Neither was working -- the most I could get with a single wall was 0.5mm, making the wall unnecessarily fragile, and the chair was able to twist out-of-square in the too-wide socket.

With two walls the thinnest I could get was 0.7mm, making the chair too much of a bash fit in the too-narrow socket.

Then hidden among the 10,000 Cura 5 settings I found Flow Equalization Ratio:

cura_flow_eq.png


Which applies where a wall width needs to be modified to fit the model.

That's normally set in the range 0-100%. So I set 200% . :)

And that seems to have worked! A single wall but now 0.6mm thick. What that setting does is to cause the forward nozzle movement to slow right down, while continuing to extrude filament at the normal rate, so creating sufficient over-extrusion to create a 0.6mm wall from a 0.4mm nozzle. Cura was already doing that at 100%, but not enough and creating only a 0.5mm wall. Setting 200% increased it to 0.6mm. Why Cura couldn't have done that by itself I have no idea.

The Prusa gcode viewer is showing the effect of the over extrusion.

What that setting is % of only Cura knows, and it seems odd that 100% isn't the usable maximum. But it's working, and by changing this % I can now fine-tune the wall thickness.

Every day is a schoolday with Cura. The next mystery is why the same settings which produce nicely-fitting brick connector clips on the BIBO, are now producing a tommy bar which won't fit in the claws on the Neptune. :confused:

How are you getting on with the Anycubic Mega? I see it is now discontinued, just like my BIBO. It's difficult to keep up.

cheers,

Martin.
 
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