Author Topic: Ender 3 - General discussion  (Read 2921 times)

Offline Will_D

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Re: Ender 3 - General discussion
« Reply #50 on: February 02, 2020, 07:13:17 AM »
Tip of the day:

You may know that there is a menu button to manually command  a filament change.
So if you want to change colour you have to watch it like a hawk!

However; If you edit the g-code, go to the layer where you want the filament change just insert:

;
;Filament Change
M600
;

and this will do it all for you.

PS: Layers in the g-code start at layer 0 so that  is at your layer height

So with a 0.2mm layer height, you want to change layers at 2mm you insert just before Layer 10 like this

G0 F9000 X48.853 Y17.354
G1 F1200 X50.399 Y15.808 E53.05569
;MESH:NONMESH
G0 F300 X50.399 Y15.808 Z2.2
G0 F9000 X52.435 Y21.308
;TIME_ELAPSED:155.534818

;Filament Change
M600

;LAYER:10
;TYPE:WALL-INNER
;MESH:Test_Pin.stl
G1 F600 X51.51 Y21.454 E53.08684
G1 X50.585 Y21.308 E53.11798
G1 X49.754 Y20.884 E53.14901
G1 X49.093 Y20.223 E53.1801


Hope this helps

Will
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Offline AdeV

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Re: Ender 3 - General discussion
« Reply #51 on: February 02, 2020, 07:26:39 AM »
Tip of the day:

You may know that there is a menu button to manually command  a filament change.
So if you want to change colour you have to watch it like a hawk!


It took me ages to find that the second time, after once accidentally finding it...

...turns out it's only there when you're actually printing something! Which seems crazy to me - I'd like to be able to pre-heat the extruder, change filament, THEN start printing....

I guess if you replace the stock mainboard with an Octaprint, such options might become available, I don't know - I've not dared go down that route yet
Cheers!
Ade.
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Offline russ57

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Re: Ender 3 - General discussion
« Reply #52 on: February 08, 2020, 04:51:30 AM »
You lot, stop it.

My son came to me and said, how about we go halves on an ender 3.
So it seems I have joined the club.
Next step, fusion 360..

Next question, what software to avoid?

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Offline Will_D

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Re: Ender 3 - General discussion
« Reply #53 on: February 10, 2020, 06:51:41 AM »
I'd like to be able to pre-heat the extruder, change filament, THEN start printing....

Just rename this file back to .gcode, stick it on a stick, stick in the stick etc

HTH

Will
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Offline Brass_Machine

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Re: Ender 3 - General discussion
« Reply #54 on: February 10, 2020, 08:45:02 AM »
...
Next question, what software to avoid?

...

I really can't think of any software to avoid. Cura does a fine job...
Science is fun.

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Offline Will_D

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Re: Ender 3 - General discussion
« Reply #55 on: February 10, 2020, 08:47:05 AM »
Time for a question:

I want to manually command (in g-code) a filament extrusion.

So I use G01 Fnnn Ennn with a 1mm diameter nozzle and 1.75 filament

My question is "What is the relationship between E (I believe this is the length of filament to extrude, not the length that is extruded) and the feed-rate given a certain nozzle diameter"?

Thanks in advance

Will
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Offline ddmckee54

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Re: Ender 3 - General discussion
« Reply #56 on: February 10, 2020, 04:12:28 PM »
Will:

I'm going to go out on a limb here, I'm not a slicing software programmer so this is just a guess - but this is how I'd do it.  To make this easier on me were gonna make a whole bunch of assumptions:
1) We going to print a line 60mm long, 1 filament wide by .5mm tall.
2) We're going to fix the filament width in the slicer at 1mm.  (Your nozzle width, which seems huge by the way.)
3) We're going to ignore acceleration and deceleration.  (We've got those new reactionless drives and can go from 0-60 in nuthin' flat.  We  could figure in accel and decel, but it makes my head hurt thinking about it right now.)
4) We going to assume that we print nice rectangular sides on our line.  They won't be, but straight sides make the math SOOO much simpler.

OK, enuff' funnin' around let's get down to the nuts and bolts.  We need to print our line but before we can print it we've got to tell the printer how many mm of 1.75mm diameter filament needs to be extruded (E), and how fast to extrude it (F). 

We know the volume of material that needs to be extruded, we know the length of the move, we know the layer thickness and we know the fixed filament width.  For our line, this extruded volume works out to 30 cubic mm.  I love nice round numbers.

We know the extruded volume, now we need to calculate the number of mm of 1/75mm diameter filament we need to get that volume.  When I worked through the calculations for the volume of a cylinder 1.75mm in diameter by 1mm tall, I got 2.405 cubic mm.   So our 1.75mm filament contains 2.405 cubic mm of extrudable material per mm of filament.  30 divided by 2.405 equals 12.474mm, we now know that our extrusion length (E) is 12.474mm.

We also know that we need to extrude that 12.474mm in the time it takes for the printer to get from point A to point B.  With our reactionless drives on our printer we're ignoring accel and decal times, so the time it takes to get from one end to the other is just the length of the line divided by the print speed.  This travel time is 60mm/(60mm/sec), or 1 second.  Did I already say I LIKE nice round numbers?  The feedrate (F) is the extrusion length (E) divided by travel time.  Our extruder feedrate (F) works out to be 12.474mm/sec.

This may, or may not, be a very simplified version of the actual calculation.  It's going to start getting hairy when you vary the filament width based on layer height like I think Slic3r does, and then add in the accel and decal times.  That's just more number crunching which is what the high-speed morons that we call computers are good at.

But I'm pretty sure that it's all based on the extruded volume required by the move, and the travel time required by the move.  Is that what you wanted to know?

Don


Too many irons, not enough fire.

Offline russ57

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Re: Ender 3 - General discussion
« Reply #57 on: February 10, 2020, 04:22:54 PM »
Which seems a far more comprehensive answer than I was thinking - the area of the nozzle  / the area of the filament = 3 approx, so 1mm of filament extrudes to 3mm, but that doesn't allow for any ' stretching' as a result of the head pulling.

-Russ


Offline Will_D

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Re: Ender 3 - General discussion
« Reply #58 on: February 11, 2020, 05:54:00 PM »
Don,

Many thanks for the detailed reply. I will work up a spread sheet based on your inputs.

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Offline beeshed

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Re: Ender 3 - General discussion
« Reply #59 on: March 14, 2020, 05:18:40 PM »
On the ME forum there is a thread about the Ender and printing gears which coincided with us getting an Ultimaker and I managed to get them to print a 1 Module 30 tooth changewheel for me. Then I found it difficult to get access to the printer so I just got my own.
Picture shows original injection moulded Hobbymat change wheel plain colour, Ultimaker print in grey, Ender print in red. The 20mm holes came out about 4 thou undersize easily adjusted with sandpaper to a perfect fit. Tooth form is fine and meshes nicely so to sandpaper the hole I held it on a bar wrapped with sandpaper and held it against a changewheel while the lathe was running (HSE pedants faint).

Bed levelling - as mentioned by Pekka I had loose bed levelling screws so had to apply epoxy + washer + nut.

Offline beeshed

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Re: Ender 3 - General discussion
« Reply #60 on: March 14, 2020, 05:27:11 PM »
Wrong picture got in there. However it shows 3 outer layers requested on the grey one and a little void because the 3rd one 'wouldn't fit'.

Offline beeshed

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Re: Ender 3 - General discussion
« Reply #61 on: March 15, 2020, 06:55:55 PM »
So the Hobbymat wheels have a 20mm hole to go on a bush to join two gears or on the spindle but the 20 tooth gear is smaller than the bush and has its own reduced size special bush. I printed a 20 with integral bush and even included the key. A touch with a file made the key fit nicely into an original gear. Feels strong enough so I will try printing a 19 joined to a 91 to use for slow feed using primes to spread the wear.
Next I went up a factor and printed a 14DP test part for a 63 tooth with the top not printed to see the fill pattern and wondered if an epoxy fill would add strength but probably it is better to have the top layer and programme more % fill. 3 outer layers filled the tooth nicely. I put  holes in it to mount it for a strength test not to make it Lego compatible.

Offline mc

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Re: Ender 3 - General discussion
« Reply #62 on: March 15, 2020, 07:54:22 PM »
Beeshed, what material are you using for printing?

Offline beeshed

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Re: Ender 3 - General discussion
« Reply #63 on: March 17, 2020, 06:43:34 PM »
Just PLA. The red was the cheapest. The grey in the first picture is also PLA but more expensive 'cos the Company bought it. The brownish gear is the injection moulded original.
Must get another colour or two for variety.

Offline tom osselton

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Re: Ender 3 - General discussion
« Reply #64 on: March 17, 2020, 08:36:14 PM »
Well I guess with this virus Iíll have to start playing with my Makerbot Replicator 2 Iíve got some water soluble fillement to try out it will be interesting to see how it works for support. Hopefully I will make some patterns for casting season.