Wednesday, November 28, 2007

My extruder is not shutting off so I can nap?

I found that my extruder was not shutting off for me when it went into its cooling mode. it also was not shutting off when it was moving from the perimiter to the inside printing. I found the bug after looking at the code fixed it and now I can nap when printing... Now I can give a cup a try printing this is good to dial in the machine. I now think I am close to printing parts for our machine..

Printing With HDPE


this time I have been printing with HDPE and have found it does not stick to Formica so I followed Forrest and Nophead and used foam board this worked but for some reason the ink or chemical the HDPE sticks to seems to leave with the HDPE is removed so it can not be used very well a second time.. So I then tryed using a piece cut from a HDPE water bottle and then glued to the foam board with a glue stick I have found this works but I do still get some curling on the first layer..

Is this suppose to be this Big??

I have not fully dialed in my machine when I first print ed a round cup the only issue was it was 3 inches across I then adjusted my axis in the preference tab there is a 1 mm = steps setting for each axis so with my caliper in hand (I highly recomend one I got this from Harbor Freight) I found a place to reference from and set the caliper to 0 then stepped one step at a time using the stepper exerciser till I reached 1 mm and set the setting to this amount. After I did this for each axis I printed a cup and got a smaller cup.


my cup is square??

I found I was getting a square cup not round then I found out I needed sync wires added when that was added it tells the boards to only let one stepper move at a time.. They are 2 wires and they are connected to each Stepper board with the Z axis being in the middle.

End Stops



We printed a little before adding the end stops to the machine. I soldered pins to the boards as
I was having a hard time soldering the wire we are using and I also have a good pair of crimpers for the small molex pins. I also had to make the flags which I used aluminum flat stock. There are only one per axis this is because the other end is set in the software with a utility.


My Extruder


my extruder is made from wood (popular)
I used my scroll saw and whittling skills to make the clamps the hardest part and prob. the first part I am going to print is going to be the coupling between the motor and drive screw. This part is made from CAPA and was not to easy to mold. the bearings in the clamps have broken down and I am getting small parts of brass in the plastic as I extrude it seems to have caused a little blockage in the extruder tip but not so bad I have not had to remove the tip to clean it. As for the c clamp this is required in order to extrude HDPE. I have had a hard time getting the stock thermistor to reach more then 170 Deg. C. I have ordered a new 100K thermistor and will post how it works. When the machine goes to warm up will start extruding at 170 and to get that I set my temp to 280 Deg. C. it might be my settings from the profiler but I am going to try it with new thermistor and see first..

Monday, November 26, 2007

last few weeks

Well it has been a busy last few weeks and I have a lot to post.. and now that my Mother board on my PC has died.. and my extruder motor has started to make a loud squeal. I now have time and a reason to post.. so stay tuned over the next few days..

Saturday, November 3, 2007


video

Here is a video of the of the extruder in action.




video

Here is a video of the robot that is working but it is not making anything yet because we are dialing it in still.

What the machine looks like

Ok here is a picture of the whole machine



Here is the extruder which is the part that extrudes out the HDPE



This is the Z axis this moves the table that the extruder places HDPE on.



Here is the Circuit board that controls the Z axis


this is one of the 8 corner blocks on the machine they are made out of oak and are drilled and then tapped fro the set screws that hold the 5/16 steel rods so they do not slide.





here is one of the corner screws I used the pulleys are commercial made and are plastic with an aluminum hub the block is there to add tension on the belt.

this is the table support I am using furniture nuts that are threading on the threaded rods which are 5/16 inch also.



this is the X axis bearing holder there are 2 rods that are parallel to each other one is connected to the x axis motor and the other idles .
here is the X axis stepper motor it is a 200 step motor

here is the x / y axis end support the y axis belt goes through it and it travles on the x axis plane


here is the Y axis motor and holder a lot of the parts are made from MDF and we had to make them a few times to get them to work
here is a close up of the x axis motor and coupling this coupling is commercial made and because the shaft of the motor and the 5/16 rod are different sizes this was a pain to line up here is also a shot of the motor mount which I made from aluminum angle.



this is the Y axis extruder mount, extruder and extruder circuit board
and here are some pictures of the extruder

The first post some history about our machine

Well this is the first post about a RepRap 3d printer my son and I are making. We have been working on the machine since January 2007. It is actually called a RepStrap because it is made from parts that are not extruded from a 3d printer.. This machine is made from most of the dimensions of a RepRap machine. the only difference is the parts of our machine that are normally printed are made from wood using a drill press, scroll saw and other hand tools. A lot of the other parts can be bought from the RepRap Research Foundation. A little but about our setup there is the carteian robot, then there is the extruder which I am trying to extrude High Density Polyethylene which seems to be a hard thing to do at times.. Then there is the computer we are using it is an older machine it has a pIII processor and is running Ubuntu 7.04 is has the RepRap host software installed which runs in java I also do not have a monitor connected to the pc I am connecting though VNC to save some space in our "lab" this all seems to be running fine as of right now.. This computer communicates to the machine with a serial port and cable.. So that is enough intro now some pictures of the printer in the next post...