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Tapping

PostPosted: Thu May 03, 2012 8:30 pm
by bdring
I'll take responsibility for the tapping. I just randomly tapped them without thinking it mattered. :oops:

I am sure Murphy will make sure less than half of you you got it right :cry:

Sorry about that.

It is not a real project unless you have to buy a new tool....M5 Tap.

If you have a #10-32 or #10-24 that should work in the same pilot hole.

Re: Not so easy

PostPosted: Thu May 03, 2012 8:36 pm
by awesomenesser
dzach,

I noticed that the holes were tapped on the wrong side too and just tapped the other side before I assembled it (Already had the M5 tap from the laser build). (The only reason I tapped the other side is that I didn't want to break all the constraints in my Inventor drawing and flip the makerslide.)

Re: dzach's Hadron build

PostPosted: Thu May 03, 2012 8:42 pm
by dzach
Nah, after all it seems to be a minor problem. Indeed I drilled another hole because I didn't have an M5 tap, but now I see that others, who have it right, still wire the carriage wires on the top face of the plate because of the heated bed. So I guess I'll just do that for the time being. I'm so close to start testing the motors I can't think of a reassembly right now.

Motion!

PostPosted: Sat May 05, 2012 2:30 pm
by dzach
We have motion!
After one dead out-of-the-box stepper driver (which I'll have to examine), all motion systems work flawlessly. In the beginning I thought there was something wrong with the electronics, the sound was so weak. Then I realized all steppers were actually moving, and moving strong they were! I don't know how other printers sound, this ORDbot is really discreet, almost a whisper.
Motion was tested with this code. Marlin gives me an error that needs debugging, parameter settings etc., next thing to do.
2012-05-05-171709.jpg
Motion!

Z-axis steppers are connected in series. There is no wobble that I can see or feel. Experimental AlFe extruder works fine but CuHotE hotend needs some more work to finalize.
2012-05-05-171811.jpg
AlFe experimental extruder

Re: dzach's Hadron build

PostPosted: Sat May 05, 2012 3:54 pm
by mxk
Congratulations!! That's a major milestone! Now the real fun begins...

Re: Motion!

PostPosted: Sat May 05, 2012 5:50 pm
by dzach
Thanks!
I gave in to perfection :roll: and changed the Y-axis to be in accordance with the drawings, i.e. top t-slot to the left and all look proper.

Other than that, I have a little difficulty getting Marlin to act properly. The hotend temperature is fluctuating, although when I heat the thermistor it shows immediately. I get the feeling that the thermistor type is not correct, it's supposed to be an EPCOS - B57560G104F - THERMISTOR, NTC, if I remember correctly, but this behavior is not normal.

That may also be the cause for an error:
Extruder switched off. MINTEMP triggered !
Error:Printer stopped deu to errors. Fix the error and use M999 to restart!. (Temperature is reset. Set it before restarting)


So back to reading the RepRap forum for answers, before I ask for help.

Re: dzach's Hadron build

PostPosted: Sat May 05, 2012 11:08 pm
by mxk
Are you using bang-bang heating, or PID temperature control? If you are using bang-bang, then oscillations of as much as +/-5 degrees around your target temperature shouldn't be unexpected.

Fwiw, I've had good results with the 100K thermistors sold by Ultimachine. I bought a bunch for future needs, so I would not be playing the guessing game again.

If you are sure you have selected the correct thermistor when you compiled Marlin, then definitely use the auto-PID tuning. Send it a command of M303 from Pronterface or the terminal screen in the Arduino environment, and it will heat up to around 150 degrees (not enough to cause any problems, but enough to get into the range it needs to be accurate) then will cycle around that about four times. At the end, it will tell you the recommended values you should use for P, I, and D in the code. After that the temperature fluctuations should be around half a degree.

Re: dzach's Hadron build

PostPosted: Sun May 06, 2012 12:41 am
by dzach
mxk wrote:Are you using bang-bang heating, or PID temperature control?

No heater yet in working condition, I should have clarified that, just the thermistors. I'm just monitoring the temperature as it's read in using an M105 code:
ok T:3.0 /3.0 B:5.0 /3.0 @:0
ok T:37.9 /3.0 B:12.3 /3.0 @:0
ok T:38.7 /3.0 B:45.5 /3.0 @:0
ok T:9.7 /3.0 B:45.1 /3.0 @:0
ok T:18.5 /3.0 B:36.7 /3.0 @:0
ok T:3.0 /3.0 B:36.1 /3.0 @:0
ok T:3.0 /3.0 B:3.0 /3.0 @:0

You can see the fluctuation in both the extruder and the heated bed thermistor outputs, same as with Pronterface. Here is a plot of about 200 values:
ORDbot-temperature.png
Thermistor temperature reading

If I heat the thermistor I get an immediate response (not shown above) and after a while it goes back to the same kind of noise.
The above is the output as read by a small script that just connects through the USB, sends the M105 command and saves the output to a file. I need the temperature data at a later stage to examine the operation of the DIY hotend.

I've disabled the PID process but it doesn't seem to matter.

Re: dzach's Hadron build

PostPosted: Sun May 06, 2012 3:19 am
by tango282
Are your ohms correct on the thermistor at room temp? (that is the thermistor is good?) The next question that popped into my head was of course with your software. As I have zero experience with printing please forgive me if you are way past this stage or I do not understand he problem correctly. You mentioned that you tested the system with a specific code (http://reprap.org/wiki/File:RAMPS1.4_Te ... ilehistory) Is that still running? I only ask because in the comments section of the Ramps wiki the author states that the code cycles on and off all of the MOSFETS and that graph definitely shows a cycle. Whew!!! 20 links of comments later (stupid rabbit holes! but I guess that is how I found the ORD Bot) Another thread I read was talking about increasing the delay in measuring to allow the ADC to catch up (http://forums.adafruit.com/viewtopic.php?f=25&t=11597) and switching the reference voltage to 3.3 due to noise (they mention USB) (http://www.ladyada.net/learn/sensors/thermistor.html) I am just spit-balling here, like I said I have no idea what I'm talking about..

Re: dzach's Hadron build

PostPosted: Sun May 06, 2012 9:42 am
by dzach
Thank you for taking the time to help me with this problems.
tango282 wrote:Are your ohms correct on the thermistor at room temp? (that is the thermistor is good?)

Yes, I measured the thermistors (disconnected) and their resistance seems ok, around 98kOhm when left to settle at room temperature, the value fluctuating very little in the decimal part. I've got 4 thermistors and they all show the same values but also have the same behavior when connected.

After I tested the motors (I have not connected any heaters yet) I loaded the Marlin 1.0.0 RC2 firmware. The test code is no longer running on the RAMPS.

tango282 wrote:Another thread I read was talking about increasing the delay in measuring to allow the ADC to catch up (http://forums.adafruit.com/viewtopic.php?f=25&t=11597) and switching the reference voltage to 3.3 due to noise (they mention USB) (http://www.ladyada.net/learn/sensors/thermistor.html) I am just spit-balling here, like I said I have no idea what I'm talking about..

The voltage on the connected thermistors measures 4.53V DC, there is no AC component that can I measure with a digital multimeter in the range of mV.

These are very useful suggestions. I'll go through them and report back.