Zortrax M200 Duet Conversion
-
Moving along nicely, just waiting on silly little bits like standoffs, wire, fans, odds/sods.
Looking like a fairly straight forward swap with plenty of room in the electrical compartment.
I'll replace the K type thermocouple with an S3D PT100/daughter board I've got sitting here as the existing thermocouple only has short wires which I understand can't be extended, probably just in 2 wire configuration as I have the Molex plugs it's fitted with. UNLESS there's a compelling reason to use 4 wires on the PT100? Any suggestions on wire gauge for the sensor?
Existing extruder heater I'm assuming is 40w/24v, so 20AWG (even 22AWG) silicone wire with a microfit 3.0 plug will easily handle the current, so that's all good.
The heat bed is a bit of a bugger as Zortrax has some unique features there:
1. It uses nozzle contact pads to set nozzle height and level check. This feature is pretty good actually, and the only way it goes wrong is if the nozzle is very dirty with built up carbon. I wouldn't mind using it in conjunction with the IR sensor, but I'm guessing it's normally open then closed on contact with the pad, where the DuetWifi uses normally closed limit switching?
2. It unplugs at the back and sits on magnets so it can be lifted out on print completion. This is an awesome feature that I want to keep. Just so handy for removing prints without stressing the Z axis.
3. The PCB bed heater appears to be glued to the back of the ally part of the build plate. It doesn't want to come off, and I don't want to damage it. It appears to have a 100k thermistor (measuring 95k on my meter) which I'm assuming will plug straight up to the DuetWifi and has the wiring incorporated in the existing loom already. The bed heater measures 3.6 ohms, so I'm at 6-7 amps @ 24v? Easy work for the Duet then at half its rated current?
I was going to do away with the perfboard altogether and stick a sheet of Printbite straight onto the heated ally plate, but the plate is not very flat at all, which I guess is compensated by the fact that Zortrax software offers only raft printing.
What I'm thinking of doing is setting it all up with the IR sensor, and just using the raft option with S3D for now.
What would be nice in the future though would be a water jet cut cast ally plate 6-8mm thick with Printbite on top and a Keenovo heater in 240v, operated by an ACDC solid state relay. I'd get the plate cut will all the same mounting holes for the locating dowels, mounting magnets, etc so it would drop straight in. There's tonnes of room in the electrical compartment, and a big fan with plenty of ventilation, so that should be fine as well. I'd use a 4 pin 240v rated surface mount plug and make a new loom for the Keenovo mats power/thermistor.
Just thinking out aloud…any suggestions?
-
Sounds good! My thoughts:
1. If you will be using a plug/socket for the hot end, then I suggest you use a 4-wire configuration for the PT100 to guard against the contact resistance increasing. Just get a microfit 3.0 connector with a couple of extra ways, which is what I did when I upgraded to PT100.
2. Depending on how non-flat and flexible the existing bed is, and whether it would be possible and safe to use clips around the edge, you might get away with putting a sheet of 4mm glass on top and printing on that.
3. When you come to upgrade the bed, I advise against using a 240V heater if you want to disconnect the bed when the print has finished, because of the difficulty of making it safe. Your bed heater is only 160W so it is easily powered from 24V, and you already have a 24V PSU providing adequate power. You could order an EcoCast plate to your required size from http://www.aluminiumwarehouse.co.uk/cutting_calc.php and attach a 24V silicone heater to the underside and a thermistor or another PT100 in a hole at the edge. Make the bed plate a little larger than the heater and the print area to leave room for fixings.
My preferred arrangement for small to medium size print beds is glass clipped on top of aluminium, with or without a thin sheet of PEI attached to the top of the glass. The PEI is painted black on the underside for compatibility with the IR sensor. The glass can be unclipped from the bed plate when the print is finished.
-
Cheers David,
That ally cut place is a hot tip! Cheers for that.
A 240x240mm piece of 8mm thick "eco cast" (I'm assuming that's the precision flat one?) for 13 quid!!
Sold at that price, I'll drill and tap the thing myself.
I'll use the 4 wire method you showed in your blog for the PT100, but I'm thinking to solder it straight on without a plug at all for best results. It's not like I'll be expecting to change it frequently. I actually have 4 pin microfits as well but bugger it. Will 28AWG wires be OK over 1.5M?
Yeah…copy that on the AC heater. Bit too ambitious for my little printer, and Keenovo have an off the shelf 200x200 24v/200w that should give that little more kick. Especially under ally without the extra thick Zortrax perfboard to heat.
Can I just rely in the thermistor in the silicone heat mat?? Does the DuetWifi software allow me to calibrate the temperature reading to show the actual temperature I take on the build surface using a thermometer probe? I'd hoped to set the hotend temp the same way as well.
I'd prefer not to use glass and am keen to try the Printbite, as I print a lot with ABS up around the 260 deg mark, and am pretty much on the same page as Digital Dentist regarding ABS printing requirements (no offense meant). It seems to be get good reviews providing it's set up all level at the right nozzle height, and I'm pretty particular setting those up.
Bit of a pain sitting around waiting for little bits and pieces to arrive when you're all keen to fire it up…..
-
I use the thermistor built in to the silicone bed heater on my delta printer. It works, but it over-reads somewhat because it is close to the heater wires and not in good contact with the bed plate. So I have to set the temperature somewhat higher than I really want, but I have got used to that. Also it gives slightly strange heater tuning results because the system has 2 time constants instead of just one as the heater model assumes. A 3mm cartridge thermistor or PT100 set in a hole drilled into the edge of the plate would be more accurate.
If you intend to connect the PT100 sensor without using a connector, then a 2 wire connection should be adequate. To work out the effect of 3m of 28AWG wire, work out its resistance. One ohm of resistance gives a temperature error of 2.5C. If you use a 4-wire connection, the wiring resistance doesn't matter.
-
I use the thermistor built in to the silicone bed heater on my delta printer. It works, but it over-reads somewhat because it is close to the heater wires and not in good contact with the bed plate. So I have to set the temperature somewhat higher than I really want, but I have got used to that. Also it gives slightly strange heater tuning results because the system has 2 time constants instead of just one as the heater model assumes. A 3mm cartridge thermistor or PT100 set in a hole drilled into the edge of the plate would be more accurate.
If you intend to connect the PT100 sensor without using a connector, then a 2 wire connection should be adequate. To work out the effect of 3m of 28AWG wire, work out its resistance. One ohm of resistance gives a temperature error of 2.5C. If you use a 4-wire connection, the wiring resistance doesn't matter.
Thanks very much for that.
So a PT100 drilled into the plate it is then.
I'll use 4 wires both in the extruder and heat bed sensors.
I understand the single daughter board can run 2 PT100's? Is that correct?
I like the idea of accurate sensors on both the bed and extruder, might as well do it right.
I went looking for sensors with 4 wires standard.
Seems I can get longer ones in 3mm, which might be nice for the heat bed as it'd cover more area?
http://au.rs-online.com/web/p/platinum-resistance-temperature-sensors/7621143/
Seems this one only goes up to 200 degrees? Are all PT100's the same?
In 10mm long (for the extruder block) it seems I can only get 2 wire, so I'd need to solder wires on as per the DC42 blog?
https://littlebirdelectronics.com.au/products/pt100-temperature-sensor-probe
Here's an ebay one with wires long enough to go straight through to the board:
If anyone has links for what would be the very best option, please feel free to put them up.
-
Yes the PT100 daughter board supports 2 sensors.
-
Yes the PT100 daughter board supports 2 sensors.
Thank you.
You beat me to it, I've edited some more questions in above.
-
The only PT100 sensor I have used is the E3D one. Do you have a distributor for E3D in Australia?
There are in theory two slightly different sorts of PT100 sensor, based on European and American standards, but according to Wikipedia the American standard isn't used much these days.
-
What's the best way to go with the fans for the Duetwifi?
I'm assuming 24v was the way to go, regardless of being always on or controlled?
The Zortrax is weird in the way that it uses a big 24v fan to cool the board (always on), but then uses 12v for the heat break and print cooling fans.
I'm happy to use 24v all round if that's the best way to go.
From what I've read it's got to be all the one voltage for this board?
-
Yes fans are all 24v. If you want to use the Zortrax 12v fans, you can do so by using a 24vdc to 12vdc converter.
Edit. That's assuming that you are using a 24v power supply. Basically, the fans are whatever voltage you are powering the duet with.
-
Yes fans are all 24v. If you want to use the Zortrax 12v fans, you can do so by using a 24vdc to 12vdc converter.
Edit. That's assuming that you are using a 24v power supply. Basically, the fans are whatever voltage you are powering the duet with.
Thank you.
I'll just buy new 24v fans rather than add a converter.
Really struggling with fitting this IR probe anywhere near the nozzle.
I'm assuming I can set the 5 (I'll just use 5 points for this small bed) locations of the level checking function in the firmware?
-
Really struggling with fitting this IR probe anywhere near the nozzle.
Me too. I have a great big fat cone shaped diamond hot end nozzle. The best I can do is offset to one side by about 17mm. Not ideal but I'll have to live with it.
-
Really struggling with fitting this IR probe anywhere near the nozzle.
Me too. I have a great big fat cone shaped diamond hot end nozzle. The best I can do is offset to one side by about 17mm. Not ideal but I'll have to live with it.
Yeah, I'm looking at about the same distance at back of the nozzle.
Too much stuff to tuck in all around the hot end.
Been at it with the prototypes all day, but might have the final take on the printer right now (hopefully).
-
When you do the probing file make sure the probe points go round the bed in a clockwise direction (Viewed from above) and the finish with the centre one
Doug
-
Bit further along.
Mounted the board with the antenna facing the ventilation holes, in the hope that I can sit my portable wifi dongle right beside the printer and get a reasonable connection.
All existing cables that are being used have been fitted with plugs to suit the Duet, time to start running all the wires up to the hot end. I'll be taking a bit of time/care with the wiring loom so it's all laid out very neatly and secured nicely at each end.
Despite looking like they are pulled tight, the stepper motor cables are quite loose….I even went for another look after seeing the picture lol. Optical illusion.
Got my dual fan/IR probe housing almost perfect (never mind the crap brown filament, I'm using it up on prototyping). The probe is miles from the nozzle but I don't care as I'll be using a precision cast ally build plate with Printbite on top, which I'll level manually with a feeler gauge like I always have.
Fans fitted are dodgy old 12v's I had laying around while I wait for my 24v fans to arrive.
-
One concern though….
I can position the nozzle for setting the height in the start so that it's over the build plate, but if I'm using the full plate for a big print the sensor will be outside the edge of the plate over open space.
Is that going to be a problem??
My understanding is that it's just used for level checking and setting the nozzle height for the first layer, and that after that the layer heights are set by the steps of the Z axis stepper.
Is that correct?
-
You can configure the XY offsets of the nozzle from the probe in the G31 command in config.g. Then all you need to do is choose bed probing points to put in bed.g that the probe can actually reach.
-
You can configure the XY offsets of the nozzle from the probe in the G31 command in config.g. Then all you need to do is choose bed probing points to put in bed.g that the probe can actually reach.
Thank you,
I understand that I can set the bed probing points, but as the print progresses past the first layer is it all right if the probe is outside the edge of the build plate?
-
I understand that I can set the bed probing points, but as the print progresses past the first layer is it all right if the probe is outside the edge of the build plate?
Yes, as long as it doesn't collide with anything or short against anything.
-
