1 Topic by EagleSeven (edited by EagleSeven 2015-07-15 15:14:34)

  • EagleSeven
  • EagleSeven
  • Member
  • Offline
  • From: Dallas, Texas
  • Registered: 2015-07-06
  • Posts: 219

Topic: Failing Thermocouple wires in CTC :(

The second thermocouple heat-block Temp sensor wire Broke yesterday.
I replaced one about a week ago, now the other has failed.
Luckily I purchased 5 , so had it ready to go in .

I think the single strand wires, in the cable,
just can Not take the bending forces caused by extruder assembly moving around so much. sad

Wire failed during a print and the printer just Stopped when it failed. sad

I routed the cable so it would not have such sharp bends,
and not clamped so tightly at bends.
Maybe that will help.

CTC Printer
Modifications Added

2 Reply by TickTock

  • TickTock
  • TickTock
  • Member
  • Offline
  • Registered: 2014-05-28
  • Posts: 263

Re: Failing Thermocouple wires in CTC :(

I think it's because your printer lacks an enclosure. ;-)  Seriously, though, sounds line a case of not enough zip ties.  It really shouldn't be moving around.

3 Reply by EagleSeven (edited by EagleSeven 2015-07-15 16:06:25)

  • EagleSeven
  • EagleSeven
  • Member
  • Offline
  • From: Dallas, Texas
  • Registered: 2015-07-06
  • Posts: 219

Re: Failing Thermocouple wires in CTC :(

LOL !
No, I think the zip-ties were too tight, not allowing the cable to move at bends,
putting too much pressure and bending wires sharply until they fail.
When they are loose there are No sharp bends.
Since the wires go to extruder assembly there's no way to keep them from 'moving around'.

BTW: I do think Enclosures Look Cool ! tongue

CTC Printer
Modifications Added

4 Reply by IronMan

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

Re: Failing Thermocouple wires in CTC :(

EagleSeven wrote:

The second thermocouple heat-block Temp sensor wire Broke yesterday.
I replaced one about a week ago, now the other has failed.
Luckily I purchased 5 , so had it ready to go in .

I think the single strand wires, in the cable,
just can Not take the bending forces caused by extruder assembly moving around so much. sad

I take it you mean thermistor and not thermocouple...

+1 there should be no movement of wires at the carriage...but as far as the hookup wiring leading back to the Control Board, that should be able to flex...stranded wire would be your friend.  You can hook some up to the thermistor leads with crimping ferrules and heat shrink, then route your nice new flexible hookup wire at will.

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 EagleSeven (edited by EagleSeven 2015-07-15 16:15:56)

  • EagleSeven
  • EagleSeven
  • Member
  • Offline
  • From: Dallas, Texas
  • Registered: 2015-07-06
  • Posts: 219

Re: Failing Thermocouple wires in CTC :(

No, the CTC printer has K-type thermocouple temp sensors, not thermistors.

the main place there is a sharp bend ,in wires, is at top of extruder assembly.
wires are zip-tied to a screw there, not allowing it to move, it can Only Bend.

CTC Printer
Modifications Added

6 Reply by IronMan

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

Re: Failing Thermocouple wires in CTC :(

Huh...I thought one of the reasons to go thermocouple was for temps over 300C...oh well!

Well, you can still try the stranded wire anyway.

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!

7 Reply by EagleSeven

  • EagleSeven
  • EagleSeven
  • Member
  • Offline
  • From: Dallas, Texas
  • Registered: 2015-07-06
  • Posts: 219

Re: Failing Thermocouple wires in CTC :(

IronMan wrote:

Huh...I thought one of the reasons to go thermocouple was for temps over 300C...oh well!

Well, you can still try the stranded wire anyway.

??? Thermocouple wires can Not be stranded wire,
they are made with solid wires, of dis-similar metals, welded together at sensor end.

CTC Printer
Modifications Added

8 Reply by IronMan

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

Re: Failing Thermocouple wires in CTC :(

Yes, solid for the actual thermocouple sensor end...beyond that you can use stranded:

http://www.pyromation.com/Catalog/w02.pdf

If you don't wish to go that route, then try creating several small 1/2" loops in the solid wire wherever the most bending occurs...this will help fight against the cold-working of the conductors.

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!

9 Reply by EagleSeven (edited by EagleSeven 2015-07-15 17:13:09)

  • EagleSeven
  • EagleSeven
  • Member
  • Offline
  • From: Dallas, Texas
  • Registered: 2015-07-06
  • Posts: 219

Re: Failing Thermocouple wires in CTC :(

IronMan wrote:

try creating several small 1/2" loops in the solid wire wherever the most bending occurs...this will help fight against the cold-working of the conductors.

Yes, that is a good idea!
If they fail again I will try that.
(there is enough extra length in cables to allow that)

Hopefully just loosely re-routing them will be enough let them Last a little longer.

BTW: I found new cables , made for this type printer, for about $2. each, total, on eBay

CTC Printer
Modifications Added

10 Reply by EagleSeven (edited by EagleSeven 2015-07-15 17:33:01)

  • EagleSeven
  • EagleSeven
  • Member
  • Offline
  • From: Dallas, Texas
  • Registered: 2015-07-06
  • Posts: 219

Re: Failing Thermocouple wires in CTC :(

It's my understanding that the Length of Thermocouple wires is fairly critical
in accurate temp measurement.
So, how much can you cut off before it stops reading correct Temp?
Or am I wrong about the Length having to be matched to circuit on PC-board ?
( Impedance matching to circuit )

CTC Printer
Modifications Added

11 Reply by IronMan

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

Re: Failing Thermocouple wires in CTC :(

I have no direct experience with thermocouples, but I would think a PID tuning would compensate for any difference in wire length.

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!

12 Reply by carl_m1968 (edited by carl_m1968 2015-07-15 17:44:13)

  • carl_m1968
  • carl_m1968
  • Member
  • Offline
  • From: Far North almost not Dallas
  • Registered: 2014-10-17
  • Posts: 6,512

Re: Failing Thermocouple wires in CTC :(

EagleSeven wrote:

It's my understanding that the Length of Thermocouple wires is fairly critical
in accurate temp measurement.
So, how much can you cut off before it stops reading correct Temp?
Or am I wrong about the Length having to be matched to circuit on PC-board ?
( Impedance matching to circuit )

You won't see any real impact until you get over 500 feet of cable. Then you will see a .0076% error in readings.

Google is your friend..

Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.

13 Reply by EagleSeven (edited by EagleSeven 2015-07-15 17:50:07)

  • EagleSeven
  • EagleSeven
  • Member
  • Offline
  • From: Dallas, Texas
  • Registered: 2015-07-06
  • Posts: 219

Re: Failing Thermocouple wires in CTC :(

IronMan wrote:

I have no direct experience with thermocouples, but I would think a PID tuning would compensate for any difference in wire length.


Oooh, PIDs are Off-Limits ! around Here LOL tongue

CTC Printer
Modifications Added

14 Reply by EagleSeven

  • EagleSeven
  • EagleSeven
  • Member
  • Offline
  • From: Dallas, Texas
  • Registered: 2015-07-06
  • Posts: 219

Re: Failing Thermocouple wires in CTC :(

carl_m1968 wrote:
EagleSeven wrote:

It's my understanding that the Length of Thermocouple wires is fairly critical
in accurate temp measurement.
So, how much can you cut off before it stops reading correct Temp?
Or am I wrong about the Length having to be matched to circuit on PC-board ?
( Impedance matching to circuit )

You won't see any real impact until you get over 500 feet of cable. Then you will see a .0076% error in readings.

Google is your friend..

Oh, Okay, Thanks for Info.
That certainly opens the 'Make it Short' option ! smile

CTC Printer
Modifications Added