Cleaning my Extruders

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.

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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.

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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.IMG_1111Please 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.

 

Makerbot Replicator X Axis Ribbon Cable Upgrade

I’ve been the happy owner of a Makerbot Replicator for almost a year now. But I’ve started running into repeated problems with the X axis motor. Well not the motor itself, but the wiring harness that goes to it. The wires go through some flexing with every movement of the Y axis and with enough flexing, the copper starts to work harden and break. It’s definitely repairable but requires patience to find the break and the finesse to re-solder it and patch it up well enough.

My solution is to use a wire that’s meant to take a few million bends; A Printer’s ribbon cable.

The donor for this project was an old inkjet printer that had been relegated to the garage for the past 2 years. Inside was a 22 conductor ribbon cable, meant to last for thousands of pages and millions of flexes.

The conversion

 

The Ribbon is essentially flat copper conductors sandwiched between a plastic support, so soldering to the pads on either end is a bit of a challenge. For this attempt, I cut the wire down to 10 conductors and soldered 5 pairs of ends together while pinned flat to my workbench.

Makerbot Ribbon Cable 2

 

 

 

Once everything was soldered together and I amazingly enough did not have to use my spare 5th conductor I taped up the ends of the ribbon cable with some electrical tape to prevent any shorting that might occur.

Makerbot Ribbon Cable 3

 

 

The cable seemed to be just the right width to place into the original holders for the wiring harness. I wedged it in place and reinstalled the new hybrid harness. Just a few checks to make sure that I had the proper length that could move and I tucked the remainder of the new and longer cable underneath the machine near the motor drivers.

Makerbot Ribbon Cable 4

Versamet 2 High Magnification Surface Microscope

The Versamet 2 is an old Metallurgical microscope used for looking at the grain structure of highly polished sample pieces in a lab. It does this by using a type of lens that directs light at your sample and looks at the reflected image at impressively high powers for a visible light microscope.

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One of the neat features is that it’s designed to take photographs of your part. The majority of the bottom half is set up to reflect the image onto a Polaroid film cartridge with an option to send the image to an attached 35mm camera. It even comes with an exposure control unit to accurately run the internal shutter.

The beauty of a reflected light microscope is that you can look at opaque objects. Vintage razor blades are a personal favorite of mine. The microscopic world is amazing in the things that you can see in a traditional microscope, but the things you can see with a reflected light microscope are that much again astounding.

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Like many of my odd toys, I picked this one up at an industrial auction. Best $25 lot I’ve gotten so far.