I was an original investor in a kickstarter called the Prometheus System. After several slips on delivery, I complained and was given my investment back. So I decided to "Do it Myself". The approach is to have two extruders and only one hot end. The extruders are Bowden style and both feed a "Y" device that allows both filaments into the hot end, but only one at a time. This idea has been around for a while and there are several designs on the internet for making this "Y". I down loaded three and printed them and then designed my own based on what I had learned. So now I have to calibrate my two new extruders and then give it a go. Pictured below are the 5:1 geared all metal extruders, the Y and the Y holder that clamps to the top of the hot end.
I now have both Bowden extruders mounted and I am printing from on of them. Its time to install the "Y" and see what happens.
Here is the system set up. I can now print from either extruder, but I must do a retraction on the current extruder before starting the other, as only one can be present in the "Y" at one time. Now I have to set up my software and slicer. Each color change will require an island or tower beside the printed object to use as a means of purging extra filament until the color changes. I will post again when I have tried it all together.
First print is black with blue center. Not much contrast, but both colors printed well. Here is a picture of the keychain I printed.
This system seems to work quite well. It requires a purge area and a wiper pad. That is what else is in the picture. Between colors, it moves to that area and then retracts one color and then feeds and extrudes until the colors have been purged. I am going to print some dice next and they will have more contrast. I will post a picture when I have them done.
So after doing some research, I guess what I am using is a prime tower in conjunction with a "purge trail" The purge trail is all about how you pull the filament out of the hot end. If you pull the filament and get stringing, you will plug up your filament path. Its important you get a good clean end when you pull the filament and this purge trail is where it is done. First there is a measured purge of filament to be sure the material is hot and uniform, then a small pull is made and then a 2 second wait for any stringing to harden and then a second pull is made. This method seems to work quite well. Once the first filament is pulled, then the printer utilizes a prime and wipe tower to make the color purge, so we are purging twice with this approach. If you look at the dice, it is not bright red. That is because my prime tower wasn't large enough and I was getting some black mixed in to cause the darker color. I am impressed with the system, but it works more because of the clever coding then the equipment.
It is good to know that you have created it yourself. Most of the people skip these daring decisions, however, you have shown encouragement of doing it.
