My Replicator hasn’t been functioning well lately. I switched back to some older filament and couldn’t get much out of it before the nozzle would stop extruding. I am beginning to believe that this is a common problem that everyone calls “clogging”, but I know that in my case, the drive gear just slips on the filament and it loses pressure.
One of the reasons that I love the Original Makerbot Replicator is that it is incredibly user serviceable. Getting to the drive gear is a piece of cake with a few hex drivers.
Once I got to my drive gear I could see how dirty it was. I’m not sure if it functionally makes a difference, but I suspected that the powdered plastic sitting inside the teeth was decreasing it’s ability to bite and drive.
For those of you unfamiliar with the extruder design, the filament comes into the top left in the following picture and is pressed between a delrin plunger and the toothed gear at the end of a stepper motor. The gear bites into the filament and forces it into the hole that you can see below it. This is the entry into the hot end where the plastic is melted and driven out of a tiny nozzle to make the part.
Using a small wire brush (Harbor Freight has them cheap) I cleaned inside the gear teeth and dusted off the filament guides. You can see in the lower picture that there is a groove running down the face of my plunger. Apparently this is normal wear. However I will be going the route of using a bearing face to press it into the teeth instead. Fortunately Thingiverse has me covered.Please note that on the back side of the plunger there are a number of tiny tiny washers. Four in my case. And I spent an hour on the floor trying to find them.