Author Topic: Homebrew engraver to 3D printer Mod  (Read 13783 times)

Offline BillTodd

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Re: Homebrew engraver to 3D printer Mod
« Reply #50 on: November 11, 2018, 04:19:25 PM »
Well ths is getting very frustrating!!!


Auto tuned the pid of the bed and extruder  without any problems , added the values into the config  , and up popped an update  , libraies updated some error with U8glib , now it will not compile .

Apparently u8glib has bee superceded by u8g2 but i have no idea how to add this to marlin - any arduino experts handy???

Managed to add the pid values to the installed version using m304 p i d and run bed and extruder preheat perfectly

more frustrating is that the thing is still randomly stopping while printing - it just seems to swith the power off for no obvious reason - it is not loose connection as first thought but i have no idea atm whhatnis causing it  : :scratch:
Bill

Online AdeV

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Re: Homebrew engraver to 3D printer Mod
« Reply #51 on: November 11, 2018, 05:09:53 PM »
Just thinking out loud - does it always stop after around the same length of time running? Like an auto-power-off function, or some electronickery overheating?
Cheers!
Ade.
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Offline BillTodd

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Re: Homebrew engraver to 3D printer Mod
« Reply #52 on: November 11, 2018, 05:27:47 PM »
No the stopping / power off appears random i.e it could be 3hours , 2 hours or as just now within a minute of starting to print  . I don't think it's the psu as it powers back immediately as the board is reset and it comfortably drives motors,  heater and extruder without dropping below 11.8v (measured on the board.)

I'll try running it woth bed heater as a test ...

Bill

Offline chipenter

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Re: Homebrew engraver to 3D printer Mod
« Reply #53 on: November 12, 2018, 03:00:03 AM »
The stepper drivers have thermal cut outs I fitted a computer fan , that stopped the dropped steps the board my have temperature cut outs .
Jeff

Offline BillTodd

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Re: Homebrew engraver to 3D printer Mod
« Reply #54 on: November 12, 2018, 05:35:33 AM »
Thanks Jeff , but all axes stop and the 12v rail disappears

I ran it last night without the hot bed and got a near perfect print (nozzle still leaking a bit). I switched to the blue painters tape as recommended by Don and it really seems to hold the print flat even without heat.

I think it must be spikes on the earth/ negative side of things . The board I have does not seem to have a separate 5v ground wire so will be reliant on the two 12v grounds which could be drawing 20+ amps peak , that's enough to cause some serious spiking/dipping of the 5v rail . 

Bill
Bill

Offline BillTodd

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Re: Homebrew engraver to 3D printer Mod
« Reply #55 on: November 13, 2018, 03:33:53 AM »
It's just completed 18 hours of printing with the bed heater disconnected ,so at least iknow the problem is caused by the heater.

Bill

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Re: Homebrew engraver to 3D printer Mod
« Reply #56 on: November 13, 2018, 03:22:10 PM »
Almost ready for a run on compressed air then!  :lol: Although that yellow is a touch bright to pass off as brass  :scratch:

Regarding the heater - the earth thing sounds like a good call; I guess the heater is thermostatically controlled on/off? Maybe when it clicks on, the current draw is occasionally enough to crash the computer... in which case, a honking great capacitor (maybe a few hundred micro Farads) across the controller's power rails would be enough to fix it.

If the heater isn't thermostatic.... back to the ole' drawing board?
Cheers!
Ade.
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Or: Zhengzhou, China. An even longer way from anywhere...
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Offline BillTodd

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Re: Homebrew engraver to 3D printer Mod
« Reply #57 on: November 13, 2018, 06:03:09 PM »
heaters are software pid using mosfet switches  . It seems to handle full load during initial warm up so it's not as simple as voltage drop  .

I'll see if i can find time tomorrow (got my head stuck in a book this evening and now , suddenly, it's bedtime!)

One thing I discovered this morning : it is possible to refom the plastic without melting it (sort of like ironing a shirt ) using a temp controlled soldering iron at 190C or so. Enables nice smooth holes and curves.
Bill

Offline BillTodd

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Re: Homebrew engraver to 3D printer Mod
« Reply #58 on: November 16, 2018, 06:44:24 PM »
Well cross fingers the extra ground wire seems to have worked.


I ran a new wire from the psu 0v to the outside of a coax power plug that connects to the arduino board .

While perusing youtube last night I found a chap talking about cooling fans for the work piece and how it improves the print. I played around with this today (while waiting, fruitlessly for E.on to fit  new smart meters) ,  and boy! does it make a difference.    just waving a small fan at the test cube straightened up the sides .

Bouyed on by this I designed and printed a fan adapter , and now I have a cube  that is 20.33 x 20.42 x 20.02  with beautiful straight sides . 

Im not sure if I can just adjust the X&Y steps per unit or whether there is a better/correct way to tweak it to size ??????


Bill
Bill

Offline Pete49

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Re: Homebrew engraver to 3D printer Mod
« Reply #59 on: November 16, 2018, 09:55:49 PM »
Nice work Bill. I'm doing a conversion too (as if I don't have enough already) 3D printer to laser engraver as I have a spare no name one to play with. I've ordered a 500 mililwatt laser so in the meantime I looking at YouTube for inspiration.
Pete
oops..........oh no.........blast now I need to redo it

Offline efrench

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Re: Homebrew engraver to 3D printer Mod
« Reply #60 on: November 17, 2018, 03:32:49 AM »
The size is probably within normal tolerances for an FDM printer.  You need to test whether the extra material is a hardware issue or an extrusion issue.  If it's hardware related, you can use regular machining techniques to measure it.  If it's an extrusion issue, you can experiment with different settings in the slicer software or possibly in the firmware configuration file.  Have you mentioned which slicer software you're using?

My workflow is:
Design in Fusion 360.
Slice in Slic3r.
Print (Smoothieware clone).

Offline BillTodd

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Re: Homebrew engraver to 3D printer Mod
« Reply #61 on: November 17, 2018, 05:13:00 AM »
I am using Cura atm (still running xp so  choices are few) 

Thinking about the size error. It is small but it would be handy to reduce it. I feel there could be a small amount of mechanical error : the timing pulleys are plastic and belts could stretch a little . But I suspect it might be 'tracking' or the spread of the extruded filament , and thus a fixed error rather than accumulated . I'll have to print a bigger cube (or square) to find out 

Pete, your laser project sound interesting ( I've watched a couple of Marco Reps videos on youtube , where he has used a 3dprinter fitted with uv laser to make PCBs). We have a couple of laser engravers at work (and a 3kW cutter) for metal marking that use 20w scanning beams - It'll be interesting to see what your machine can do :-)
« Last Edit: November 17, 2018, 05:41:47 AM by BillTodd »
Bill

Offline BillTodd

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Re: Homebrew engraver to 3D printer Mod
« Reply #62 on: November 21, 2018, 05:08:20 PM »
well, 4 hrs into a 12hr print of the engine base (now wishing I'd have spent more time tidying up the internal faces as every little nook and cranny needs a million movements to print!

Bill

Offline BillTodd

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Re: Homebrew engraver to 3D printer Mod
« Reply #63 on: November 22, 2018, 04:03:34 AM »
Ha it worked :)

Bill

Offline BillTodd

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Re: Homebrew engraver to 3D printer Mod
« Reply #64 on: November 25, 2018, 12:40:58 PM »
Well the engine works  :D

Needs a few mods tonthe clearances still but it works!

Bill

Offline S. Heslop

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Re: Homebrew engraver to 3D printer Mod
« Reply #65 on: November 25, 2018, 04:43:21 PM »
That's pretty awesome!