1 Topic by seagel007

  • seagel007
  • Newbie
  • Offline
  • Registered: 2014-07-06
  • Posts: 4

Topic: Odd temperature drop at the start of a print

Hello Soliforum!

I am posting for your help on a rather odd "issue" that I have been having. I put issue in quotes because it has not yet caused any real issues, but it is certainly irregular. When the printer reaches the target temperature, the start Gcode begins as it should, but the moment that the printer actually starts to print, the temperature of the print head nosedives to 40-50 degrees below where it was. It hasn't caused anything other than a bit of roughness at the base of a print, but it strikes me as something that is clearly wrong. I am printing PLA at 200 degrees C with no heatbed on the Solidoodle 2 Pro. I have an extruder fan mounted and running on a separate power supply. The printer is also in a styrofoam box I made to reduce noise and drafts. I haven't updated my PID in a while ( last time was when I added the fan), but I don't think that that would cause such a severe drop. It usually takes about 30-40 minutes to regain the normal temperature, where it stays nicely. I have posted a screen shot of the temperature curve. Any help would be great! Thanks in advance!

~Alexander

2 Reply by grob

  • grob
  • grob
  • Member
  • Offline
  • From: Sydney, Australia
  • Registered: 2014-01-02
  • Posts: 900

Re: Odd temperature drop at the start of a print

Hi seagel! Welcome!

Doesn't sound normal at all, something is wrong!

Unfortunately the screenshot hasn't stuck - you'll need a few more posts before being able to post attachments here. Can you upload it to imgur for now and post the link in text? We'd need to see that before having a guess at what's going on, it could be many things!

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

3 Reply by wire10ga

  • wire10ga
  • wire10ga
  • Member
  • Offline
  • From: Arkansas
  • Registered: 2012-09-14
  • Posts: 665

Re: Odd temperature drop at the start of a print

Check for bad wiring / connections on the hotend or thermistor.

SD2 - Glass Bed, Fans on PCB and Y motor, Custom enclosure
Slicer - Simplify3D

wire10ga's Website

4 Reply by IronMan

  • IronMan
  • IronMan
  • PRINTiT
  • Offline
  • From: SC
  • Registered: 2012-09-14
  • Posts: 1,269

Re: Odd temperature drop at the start of a print

wire10ga wrote:

Check for bad wiring / connections on the hotend or thermistor.

+1...

Also, you said that it takes 30-40 minutes to recover?  That is an incredibly long time...How long does it take to heat up initially?

SD2 - Stock - Enclosure - Heated Bed - Glass Plate - Auto Fire Extinguisher
Ord Bot Hadron - RAMPS 1.4 - Bulldog XL - E3D v6 - 10" x 10" PCB Heated Build w/SSR - Glass Plate
Thanks for All of Your Help!

5 Reply by seagel007 (edited by seagel007 2014-12-22 20:27:01)

  • seagel007
  • Newbie
  • Offline
  • Registered: 2014-07-06
  • Posts: 4

Re: Odd temperature drop at the start of a print

It takes about 3 minutes to heat up. That's why the long recovery seemed odd. It wont allow me to post any Imgur link. It says that I am over my limit. Go to imgur and post this code after the url   hIM2KC6


The start Gcode begins almost immediately when the red line passes the purple target line. it goes through the whole process, but then as it starts the print, the temperature plummets. The wiring appears to be sound.

6 Reply by wardjr

  • wardjr
  • wardjr
  • Moderator
  • Offline
  • From: Minnesota
  • Registered: 2013-06-10
  • Posts: 5,624

Re: Odd temperature drop at the start of a print

Just a random thought.
In your slice profile is there a chance that you have the extruder first layer  temp set to one temp and the other layers set to a much different temp?   Of course this wouldn't explain the temp being able to recover.

Printit Industries Model 8.10 fully enclosed CoreXY, Chamber heat
3-SD3's & a Workbench all fully enclosed, RH-Slic3r Win7pro, E3D V6, Volcano & Cyclops Hot End
SSR/500W AC Heated Glass Bed, Linear bearings on SS rods. Direct Drive Y-axis, BulldogXL
Thanks to all for your contributions

wardjr's Website

7 Reply by seagel007

  • seagel007
  • Newbie
  • Offline
  • Registered: 2014-07-06
  • Posts: 4

Re: Odd temperature drop at the start of a print

I did check and this is not the case. Thank you though!

8 Reply by jagowilson (edited by jagowilson 2014-12-23 02:17:24)

  • jagowilson
  • PRINTiT
  • Offline
  • Registered: 2014-09-14
  • Posts: 1,701

Re: Odd temperature drop at the start of a print

Post your slic3r settings under the Filaments tab, just to be sure. You can attach images with less than 10 posts. You just need to make sure you click "Add File" after clicking "Browse..."

Move the extruder to all four extreme corners, and the center. Inside the wire sheath, is there any tension? If there is, you will need to fiddle with the wiring and find out what's being held up. It's a good place to start.

Another thing is the plugs they used for my hotend thermistor were cheeaaap and came off easily. Perhaps there is a sloppy connection there. Consider splicing the thermistor and the wires connecting to the motherboard together instead.

Maybe try heating up the hotend and move the extruder left and right, back and forth. Does the temperature plummet? Don't do this too long without doing some extrusion because the stock hotend will clog if left hot without extruding for too long.

Worst case if you absolutely cannot resolve it there's always the option of an e3d upgrade (all-metal hotend which replaces the stock hotend).