Thursday, March 17, 2011

More work done

It's getting there...

I got the motors mounted, the coolant tank done, radiator mounts made and the PID mounted into the front faceplate. I also mounted the circuit boards but I really don't like it- I'm going to figure something else out so it's just temporary.





 

Saturday, February 12, 2011

Hot end done

I was able to finish up the extruder hot end. I had to remake part of the heater section as I had previously made the hole for the resistor too big- now it's a perfect fit. The water fittings are .375" OD since that's the most common size tubing used on PC water cooling pumps, which is what I'll be using. I also felt using .25" tubing would have restricted the coolant flow too much given the estimated length of tubing necessary.

Friday, February 4, 2011

Extruder construction

I started building the extruder and it's definitely a bit of work to build it this way as it's entirely welded from stainless steel. I still need to weld in the inlet/outlet fittings to the water jacket. The nozzle is made from two brass pieces silver brazed together and you can see the hole for the enamel resistor. The nozzle size is .4mm and it attaches to the stainless tube with a set screw so I can easily swap/replace the nozzle/heater assembly. There are also two small holes in the bottom near the water jacket so I can push out the liner if need be. I sure hope this thing works...

Since the extruder will be driven using a stepper motor I'm going to attempt to make my own worm drive gear using some spare ACME rod I have. The worm gear will be cut from a Delrin blank- should be fun and at the very least a good learning experience. :)


I also had a whole bunch of parts show up and the drive belts should be here early next week- woohoo!







 

Tuesday, January 25, 2011

Now that's what I call a heat sink

I finally got the Linistepper driver boards and the parallel port breakout board soldered. The Linisteppers require a large heat sink and this one should hopefully fit the bill- it measures about 7" square by 3" thick. I'm using the Linisteppers to handle the CNC machining using EMCEventually I hope to add another driver board for a four axis milling setup.

Thursday, January 6, 2011

Got a radiator

I obtained a small heater core for use as a radiator for the cooling system for the extruder and the high speed milling spindle. It measures about 9.5" x 6.375" x 2". I modified the heater core by cutting the ends off the tubes and fitting hose barbs to the inlet and outlet. I'm going to run coolant lines to the extruder and spindle using quick disconnect fittings so I can easily swap them. 

After reading multiple discussions on the CNC forum it looks like cooling fans probably will not be necessary since I really do not plan on using anything more than a 1.3kW maximum spindle. I still need to find an inexpensive pump...

Sunday, January 2, 2011

Liquid cooled extruder revisited

I'm finally getting back to working on this- seems like it's been forever! I realized there were some problems with my previous liquid cooled extruder design so I designed a new version. The new extruder has a delrin liner and a removable nozzle similar to my original concept. The heater element is a simple power resistor but I'm going to try a vitreous enamel resistor in a small aluminum block as well. 
power resistor version


enamel resistor version

Sunday, May 16, 2010

Building the chassis

It's finally starting to take shape! The footprint is roughly 11" x 11". It's still missing the rear reinforcing plates. The lower rear plate will serve as the stepper motor mount for the Y axis and the base plate that holds the Y axis (which is not yet bolted down) is Delrin for now- I'll eventually replace it with a 3/8" thick Mic6 cast aluminum tooling plate.

The Igus linear slides are so nice- just bolt them in place and you're good to go. No need to worry about rails not being in alignment or binding in the system.