Thank you so much for the pictures! It is really helpful. How about the black plastic nozzle cover. Does it simply unclip? Regarding the heated bed, I did buy this: 150 mm X150 mm 24V 100W 3M tape NTC100K in center 3D printer Heater Pad 1 PC | eBay
For what it's worth, the stock plate is 170mm square. Magnets are 2.5" on-center. They are Neodymium N42 3/4" diameter x 3/32" thick. The pocket is deep enough to put in 1/10" thick magnets. Can someone lay out a heater PCB with the magnets locations to have .9" clearance holes? Just wondering if someone was into taking on this quick development effort for cube 3.
My parts have finally arrived, so I can start putting it all together. But still struggling with the thermistor issue. Took the head apart today, measured the resistance of the thermistor. I can confirm it is 200k. Thermistors are glued in, I don't see the way of removing them without damaging. How can we identify the thermistor used in Cube 3? Anybody any ideas?
You can guess at the package size and see what is commercially available in that package. Once you find the package, you should be able to get the true dimensions from the spec sheet.
Thermistors are usually specified by their "Beta" value, which is a function of their resistance value at 2 different temps. It's usually 25C on the low end, and 85 or 100C on the high end. In order to replace an unknown thermistor, you calculate the Beta and find another with a value that matches. I think I made a spreadsheet that does the Beta calculation for you.... (it's not super complicated) I just can't remember where I put it. I can't remember if I actually did the Beta for the Cube 3's thermistors. I remember not having a lot of luck finding a replacement for them, but that was probably before I learned how to calculate the Beta. I got most of this info from Reprap.org, I believe. Thermistor - RepRapWiki MeasuringThermistorBeta - RepRapWiki
I was doing some search and looks like previously 3DSystems have used Semitec 204GT-2 for some older printers, it's beta value is 4338 (25/85C), which is now replaced with 204NT-4 (same beta). I am planning to get them and compare the values. P.S. Still cannot find it anywhere in stock :/
I think this is where I got stuck, as well. 200k thermistors are just not very common. Maybe I'm overlooking something obvious, but I don't know why you couldn't just use two 100k thermistors in series. As long as you can fit them both in the heater block, I think it should work fine. And 100k thermistors are a dime-a-dozen. You can buy EPCOS B57540G* clones on Amazon for a couple bucks a bag.
That's exactly what I was thinking about today! Get two 104NT-4's in series. According to the table, the readings are almost exactly twice smaller. Might give it a try.
Found these: TR133 SERIES 200K OHM THERMISTORS - McShane, Inc. Any clue as to the package type behind the glue?
Do they carry 100K thermistor in the metal tubing as well? I'd need them for my e3dv6 as theirs are **** expensive!
Found a possible replacement: Amphenol makes a 200k axial NTC with a beta of 4365K. They aren't crazy cheap, but they aren't terrible. Digikey has them in stock for $2.66/ea. And they actually have them in stock! AL03006-111.3K-123-G1 http://www.digikey.com/product-detail/en/amphenol-advanced-sensors/AL03006-111.3K-123-G1/KC014G-ND/136415 (They are listed as having a +/- 10% tolerance, vs 3% for the semitech, but I think for this application the difference shouldn't be too noticeable.)
Nice find! I think I'm going to give it a try! I also bought these: 10pcs NTC Thermistor 200K ohm 1% Glass Encapsulated 2mm Temperature Sensor | eBay B Value(R25/50℃) 3900K 1%, which is almost the same as 204GT-2 at this temperatures.
Hmm, I should graph the temp slope for these and see if that's an increase or decrease in temp. If that's a 100 Ohm difference around 200C, that would be about a 10C increase... which is what I think is the temp increase needed to stop all the nozzle clogs!
I think you're going to be disappointed with 3900k replacements. I found the function for finding a specific temp/resistance of a thermistor using the Beta and 1 other set of R/T values. The resistance for the 4338K Semitec @ 200C is around 900 Ohm. At the same temp, the 3900K is almost twice that resistance. (I found the formula on Daycounter: Steinhart-Hart Thermistor Calculator it's the 4th one down)
Interesting find! Anyway, the ones I bought are 3900 at 25/50 C, and GT-2/NT-4 are 4338 at 25/85 C. Little bit confusing, so I am still waiting for them to arrive from China. Will try to compare the readings once I have them.
Yeah, a Beta value isn't very accurate outside the temp range it's listed for. (Is it just me or is B25/50 a really odd range?) It would be better to run it through the full Steinhart-Hart equation, as that should approximate the curve much better at any point. But I just figured out how to do the easy one! Coincidentally, I just learned how to do a "trendline" for points on a scatter plot in Excel. You can even have it give you the formula for the graphed curve. I wonder how close that formula would be outside the Beta range. Anyway, now that I've got a good idea what the resistance is of the stupid 200k thermistors @200c, I'm going to do the same thing for a sample of 100k ones and see if the math rules out putting 2 in series.
The range looks a bit odd to me too Got a bunch of thermistors today, gonna do some tests in the evening
Looks like Mouser has Semitec 204NT-4 in stock for $3.21 each. http://www.mouser.com/ProductDetail...qs=rGO4O3Mig4jOFtoFBSLV4g==#.WNByPkkVzr0.link I also found a Honeywell thermistor that is 4261K over 25/85. Pretty close to the Semitec's 4338. They are $1.70 each at Mouser. I think they are little bit bigger than the Semitec ones, though, so they might not fit properly. http://www.mouser.com/ProductDetail...qs=F1jq4PciTHtR1RDq1ANxyw==#.WNB0agpSRyw.link Disregard the Amphenol ones I linked earlier... I just noticed they only go up to 200C.
Hahah, no, no injuries so far Didn't have much time for testing. I just did a brief testing at the room temperature and the readings where the same Will do some more in-depth testing very soon!
Anybody have spare nearly empty abs and pla cartridges? I love the ideas in this thread... but I literally can't afford to make any mistakes, so I'll just deal with the original for now. How much would you guys be willing to sort with the near empty carts for? Dm if you can help.
So@eychei arent you willing to play further with the firmware and see what can we come up with? I'd love to discover which is the Gcode that "starts print of .cube3 file in printer's memory" so we don't have to re-send over and over the same file via WiFi.... for example. Or how to turn off the cooldown forced wait we're tied to :?
Hi, i am really sorry i can't put more work into this project. You can put your files onto a usb drive and start from there if you want. No need to send it over WiFi. -e
Hi, before I want to congratulate you, you've done a great job with the firmware for cubepro, I need your help about the image695.hex file, how do you do for debug?, do you think that Can I modify the versión firmware for install all characteristic of cubepro 2 into cubepro 1. I just open de firmware in IDA. thanks and best regards.
Maybe a stepper is overheating, nobody seems to include ambient operating temperatures in their 'It won't work' posts...
