Orion Extruder Not Coming Up To Temperature

[sbarner]

We've had an Orion Delta in service for over a year and it suddenly stopped reaching temperature. It comes up to around 210 degrees and then won't go any higher, so if the target temperature of the print is higher than that, the print doesn't start. The printer just sits there, with the temperature fluctuating between 207 and 210 degrees. I haven't tried to check what the actual extruder temperature is, because this doesn't seem to be a calibration problem, but rather a voltage issue. I'm not sure how to check the voltage other than that the voltage available at the board connections where the pairs of white wires that run up to the extruder plug in is 4.96v at each connection. I can't really see where I should check voltage at the thermisters. What would be really handy is a step-by-step troubleshooting guide for this type of issue.

[Xenocrates]

Here's my bet. One of the hotend resistors went out. Go ahead and check what the resistance is. It should be ~3.4. If it isn't, you have a resistor issue, and my suggestion is to replace the resistor with a heater cartridge. See the Tutorial here from Geneb.

I'll add it to my list of things to write up a troubleshooting guide for, as I'm currently working on some course material to help out at the college I attend.

[sbarner]

You were right on the money. I didn't realize that you meant that the resistance should be about 3.4 ohms for the pair of resisters in parallel, so I clipped the leads and found that one was at 8.5 ohms, while the other was dead open. I went ahead and ordered a pair of the heater cartridges from rp_one_labs. Since the original resisters should be pulling around 42 watts at 12V and the heater cartridges are 40w each, I am assuming that it might not be wise to install more than one. I will report back as to my results, but I expect it to be favorable. The original resisters are only two bucks apiece from SeeMeCNC, but the heater cartridges are not much more than that (probably less, when shipping is factored in) and I wasn't impressed with the condition that the originals were in after what i would call "limited use."

[geneb]

Do NOT use two heater carts in that hot end! One is more than sufficient.

g.

[sbarner]

A follow-up on this project. I replaced the two resistors with a single heater cartridge and replaced the thermistor at the same time. I used the project as an opportunity to wire in disconnects for all the hot end electricals. All that worked very well. While I was at it, I also upgraded the arms to the new ball joint type. Once I figured out how to change the settings for the horizontal radius and arm length (documentation in general from SeeMeCNC is decidedly hit or miss), the prints came out pretty well. I can't say that I see any improvement resulting from the ball joint arms, other than I don't have to be concerned with the rods walking out of the universals anymore. My next task is to figure out how to reduce the amount of stringy plastic left behind when the filament retracts and the extruder moves to a new location.