obligatory obscure reference

Soon after I started testing the Mk7 head it stopped moving plastic, period. I had a working Mk6 handy and a Mini MakerFaire to attend, so I fell back to the Mk6 and decided to let other people debug the Mk7.

However, nobody on the MakerBot list really had a reason or a fix I liked, so I took it apart to fix on my own.

The first thing I discovered was that the pressure mechanism for pushing the plastic against the stepstruder was not pushing hard enough, due in part to scratches on the head’s surface.

The second — and more important — thing was that the stepstruder gear was filled with shreds of plastic. It came off easily, so like the Mk6, just pushing the plastic harder would clear the junk out of the motor.

But how to do that?

Like this.

It’s really that simple. Grab a spare M4 bolt from your parts kit, buy a wingnut at the local hardware store and glue/Loctite the wingnut to the end of the bolt.

I set it up, dialed in a temp of 240C (see earlier posts about temperature), and it forced plastic through with no problem at all. Even a 5 minute run ran without any problems at all.

Now to print some test models….