Bed Temp Change after uploading firmware on Taz5

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dutchhome
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Re: Bed Temp Change after uploading firmware on Taz5

Post by dutchhome » Tue Mar 24, 2015 11:27 am

kmanley57 wrote:The problem is the PTFE tube does this:
|
( - hole for the bolt
|

when you put the hard filament through. The amount of the tube that is left there after the drilling is
small and it stretches/thins it out as the hard filament is pushed past the hobbed bolt.

Thus the fit is now loose there for the flexible filament. You are not gripping it as well and can get feeding/retraction problems. Ooze!
This makes so much more sense! Thanks for the explaination. I kept wondering why ABS and PLA filament was so harsh on the PTFE tubes as they seem pretty sturdy.
Lulzbot TAZ 4.1
Upgraded to Hexagon Extruder
Converted old extruder to Flexystruder 1.1

billyd
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Re: Bed Temp Change after uploading firmware on Taz5

Post by billyd » Tue Mar 24, 2015 8:53 pm

Wolfie wrote:
billyd wrote:How do you do the PID calibration?

Ps In simplify 3d, the Y axis is reversed from Slic3r. So the Gcode offsets you enter for tool 1 (the second extruder) have to have the same value for x, but for y, you need to put in the absolute (positive) value of the y value you entered in Slic3r
THAT explains a lot! You would have thought the guys from S3D would have mentioned that in at least one of their emails I got on this matter. Anyway, I have resorted to putting the offsets in the firmware, that way the gcode doesn't have to contain it. Think it will be easier in the long run. First print off the bed and I am within 1mm in the Y and looks like right on in the X. Printing test 2 right now.

As for the PID cal...

Send
M303 S230

Wait. It will ramp up to 230 deg (change the 230 if you got pla in the head). It will cycle several times. Finally it will cool. Be patient, this takes a few minutes. You will get a "complete" statement back. Wait until you see the complete because it reports P,I and D several times during the process, ignore those. The ones at the complete statmentwill spit out the 3 data points you need, Kp, Ki and Kd.

Send:
M301 Ppp.pp Ii.ii Dddd.dd

Repace pp.pp, i.ii, ddd.dd with readings from the test.

Send:
M500

This will store the setting.

Send:
M303 E-1 S100

This will heat the bed up and run the same test. Again, wait. Takes longer than the head.

Send:
M304 Ppp.pp Ii.ii Dddd.dd

Again, replace pp.pp, i.ii, ddd.dd with values returned.

Send:
M500

That stores the values in EPROM.

Now, I also edited my firmware copies and placed the lines in the firmware. Its in Configuration.h

I am working with the dualie which has budda hot ends so my firmware looks like this now:
// Buda 2.0 on 24V
#define DEFAULT_Kp 14.09
#define DEFAULT_Ki 0.75
#define DEFAULT_Kd 66.00

And for the bed:
//24V 360W silicone heater from NPH on 3mm borosilicate (TAZ 2.2+)
#define DEFAULT_bedKp 164.79
#define DEFAULT_bedKi 19.37
#define DEFAULT_bedKd 350.54


The bed will not change from dual extruder to single hex. The hot end settings WILL change. You will have to run the M303 command for each head. Also, there are no settings for the 2nd extruder, they are shared so you only need to run it once with the dualie.

To send the commands, you can use pronterface or the tools in S3D. All commands must be caps M303 not m303. S3D doesn't cap them for you, pronterface does. In S3D, turn off the "Verbose" check at the top to stop the temp monitor clutter when doing these tests.

For doing extruder calibrations, I made a handy tool with everything you need:
http://www.wolfiesden.com/TAZ/ExtruderCal.asp
Thanks this is great.

Ironically when I went from the single hex on my Taz 5 to the dual extruder, my PID's for the extruders are perfect, only the bed PID settings weren't working. LOL go figure. Strange.

billyd
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Re: Bed Temp Change after uploading firmware on Taz5

Post by billyd » Tue Mar 24, 2015 9:08 pm

PS I thought the flexistruder was strictly for flex type filament only and not ABS?

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dutchhome
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Re: Bed Temp Change after uploading firmware on Taz5

Post by dutchhome » Wed Mar 25, 2015 7:44 am

billyd wrote:PS I thought the flexistruder was strictly for flex type filament only and not ABS?
To understand why the flexistruder exists you have to consider why the standard extruder doesn't work. When you feed filament into a "standard" extruder (is there a specific name for this?), the filament is squeezed between the hobbed bolt and a ball bearing. Although there is a hole in the extruder body to guide the filament, there is a small gap on either side of both the bolt and the bearing. With hard filaments like ABS or PLA this is no problem as the filament is rigid enough to span the gaps. With flexible material, the filament can bulge out (it is like pushing on rope) and jam.

The flexystruder solves this problem by keeping the filament in a tube the entire way and only a small notch is removed to allow the hobbed bolt to grip the filament and push it along. There is no gap for the filament to bend. In order to apply enough pressure on the hobbed bolt, a screw presses against the tube on the other side of the bolt.

There is nothing that prevents this from also working with harder filaments. In fact, the two extruders are working almost exactly the same way. What kmanley57 was describing was why the PTFE degrades so quickly when using the harder filament. Because it is so rigid, it doesn't give when squeezed between the PTFE tube and the hobbed bolt. Since the filament is harder than the tube, it acts like sand paper grinding away at the tube anywhere it is rubbing. Eventually this can degrade the tube enough that gaps can start forming that would allow the soft filament to buckle and jam.
Lulzbot TAZ 4.1
Upgraded to Hexagon Extruder
Converted old extruder to Flexystruder 1.1

kcchen_00
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Re: Bed Temp Change after uploading firmware on Taz5

Post by kcchen_00 » Wed Mar 25, 2015 9:39 am

On other direct drive systems, the tension between the idler and hibbed bolt isn't a problem. Any gap between the hobbed gear and extruder body is the biggest culprit. Printing an adapter for ALU direct drive mechanisms were a good fit.

I think with the printed extruders on these printers, it could be possible to modify the normal extruder design to get a better contour with the hobbed gear. Which should reduce the gap... similar to what the flexystruder accomplishes. Though I'm sure someone smarter than me has already tried, which is why we have the flexystruder design...

billyd
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Re: Bed Temp Change after uploading firmware on Taz5

Post by billyd » Wed Mar 25, 2015 10:27 am

So long story short it's a bad idea to use the flexistruder with anything but soft filament, which is what I've read elsewhere. You can run a gas engine with alcohol, but it's still a bad idea if you want a working engine tomorrow.

billyd
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Re: Bed Temp Change after uploading firmware on Taz5

Post by billyd » Wed Mar 25, 2015 1:21 pm

My PID values are not sticking. If I restart the printer the bed goes right back to heating up to 2° below the set temp and stops. Yes I send the updated values, and yes I send the M500 command. The extruder values stick, but the bed values do not. If I resend the PID values for the bed, it functions correctly until I power off. Any ideas?

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dutchhome
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Re: Bed Temp Change after uploading firmware on Taz5

Post by dutchhome » Wed Mar 25, 2015 1:25 pm

You can either make the changes in the LCD (these changes are stored in the EEPROM, I believe) or update the values in the firmware and reflash it.
Lulzbot TAZ 4.1
Upgraded to Hexagon Extruder
Converted old extruder to Flexystruder 1.1

billyd
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Re: Bed Temp Change after uploading firmware on Taz5

Post by billyd » Wed Mar 25, 2015 1:37 pm

dutchhome wrote:You can either make the changes in the LCD (these changes are stored in the EEPROM, I believe) or update the values in the firmware and reflash it.

I can't locate the Bed PID's in the firmware menus. I can only find the extruder values.

Are you saying I should reflash with a revised config.h? Why won't the M500 get the values to stick?

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dutchhome
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Re: Bed Temp Change after uploading firmware on Taz5

Post by dutchhome » Wed Mar 25, 2015 1:46 pm

Sorry, I have no idea. I don't know much about the Marlin firmware or how/when it writes to the EEPROM. Sounds like your only option is to set the bed PID values in the configuration.h file in the marlin firmware and recompile/upload.
Lulzbot TAZ 4.1
Upgraded to Hexagon Extruder
Converted old extruder to Flexystruder 1.1

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