Broken Down Duplo 645 Cutter

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printox

Active member

• Jan 20, 2025

• #1

Greeting print community! I have a Duplo 645 with cutter cycling issues. I replaced the brushes on the motor and now it cycles inconsistently. Instead of the blade being in the up position it variably falls in the middle range. Any ideas? Thanks

 

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Repro_Pro

Well-known member

• Jan 21, 2025

• #2

Sounds there may be something wrong with the contact of the brushes.

 

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printox

Active member

• Jan 21, 2025

• #3

I was thinking since the motor runs the brushes were ok. The brushes were almost completely gone. I bought a kit of 10 different brush sizes and we cut them down as a guess and one of the guys in our shop soldered them to the original caps.

 

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Repro_Pro

Well-known member

• Jan 21, 2025

• #4

Check the surface of the commutator, it may need cleaning/polishing.
Also, make certain the surface of the brushes is pressed evenly against the commutator.

 

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printox

Active member

• Jan 21, 2025

• #5

I'll try that. Thanks for the help.

 

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Pennypicher

Well-known member

• Jan 21, 2025

• #6

Check the motor as said, Also the gears that drive the motor/knife assy. No parts are available for the 645 knife/motor unit. There is a sensor that detects the knife in the up/home position so you should be getting a knife error

 

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printox

Active member

• Jan 21, 2025

• #7

Thanks, the sensor is rough. The person I bought it from, used a foreign cable and/or sensor. It looks like it should be a problem. The not cycling home position only happened after we tried fixing the motor. Apparently I was supposed to use graphite instead of just carbon for the brushes. Plan to switch that out and clean the surface as advised.