Heated Bed Pt. 3 Finished!

So over the past few days I have worked on my heated bed, and have finally completed it and tested it.
My heated bed consists of:
1 .25" x 12" x 12" piece of 5052 Aluminum
2 130w 110v flexible heaters rated to 300F wired in parallel
K type thermocouple
PID controller
Solid State Relay
Adhesive backed PET film

I wanted to maximize my build area on my bed so I decided that I would not have any obstructions on the top of the bed. With this design specification I really limited my options of mounting the heated bed.

What I decided to do was drill into the sides of the plate, and tap a 1/4-20 hole for the thermocouple, and drill over sized tap drill holes for the legs. The legs of the bed are held on by 8-32 self taping hex head screws with stainless washers between the bed and leg to help minimize heat transfer into the legs. The bed is run at 220F on my pid controller since there is a little lag between the actual temp and the location of the thermocouple, actual bed temp stays between 225 and 235 which is perfectly acceptable to me.

After mounting this up I attempted a build using painters tape, this was a failure, parts would just rip off the bed once they got about 1" high, so I moved on to the PET film. I haven't printed anything over an inch yet put the objects really stick well to the PET.


I have now started work on my version of wades extruder, which is printed I just have to put it together and see if it works. I need to create a filament dispensing solution (have the parts, need to design/print some additions), increase my resolution (stepper pulleys), and lastly I want to go ahead and make a new extrusion head for my MK5 hot-end that has a .34mm orifice aka #80 drill. I have alot to do, and so little time, Im also thinking of picking up 2 high resolution steppers and looking into new electronics, but thats just me thinking.

Pictures:

From Boxed Reprap

From Boxed Reprap

From Boxed Reprap

From Boxed Reprap

From Boxed Reprap

From Boxed Reprap

And I printed this lock out from Thingiverse:

From Boxed Reprap

It took some slight modifications post print but it works really well.

Extruder Upgrade Part 1

Im working on many upgrades at once, all while removing the transmission out of my daily driver car. Today I decided that I need to start working on my switch over to the RepRap host software. I have decided on making this switch from ReplicatorG for a few reasons:

1. The 5D firmware is much easier to modify and then upload to the electronics than the ReplicatorG compatible software.
2. I want to use a stepper motor for my extruder, and have it supported by firmware and by the host software.
3. After extensively playing around with Skeinforge I have minimized blobs and stringers to the best extent possible (for me) but im still not happy with my prints build quality, and I believe that a stepper based extruder will help me achieve this.

So today I attempted to prints, both of the gears for Wade's Extruder. The large one started to warp and I canceled the print 4 layers into it, it may have finished fine but I didn't want a slightly bent gear. The other gear (11 tooth) printed well enough that I am satisfied with it, I did file the teeth and other surfaces to give a better finish and to help make the gear run smother when it is all assembled.

Things that I need to really get finished include the heated bed, and I want to make the resolution a little finer, the involute profiles cone out a little funky on some teeth and decent on others, I believe this is happening because there is not enough resolution to produce small detailed involute curves, especially with my full stepping drivers.

Pics:

1st Mendel Part

I was bored today while working on my car so I decided to print my first Mendel part, I wanted it to be a quick print, but also a quite demanding print. So I decided upon Z-driven-pulley_20ff. Here is the final part:





Well my biggest problem is that since my Y axis is not fully constrained I get some weird movements in some of the teeth. one side of the y axis is attached to a belt/motor, the other side is free to move as it wishes (kind of like a spring). To fix this I am going to go ahead and add the second step motor to the y axis.

As is the part may work, I do not have any timing belts of the correct pitch to test it on, but I do believe it may work, just not perfectly.

Also today I will share with you my first ever print, from a few weeks ago, it was supposed to be a whistle but it printed at an angle since the bed was not attatched to the z axis and was sliding around a bit. here it is:

Heated Bed Pt. 2

All of the supplies to build my heated bed platform are now in:
1ft x 1ft aluminum sheet, PID controller, K type Thermocouple, and the heating elements.

I have attached the thermocouple to the bed by drilling in to the side of the bed and tapping it to 1/4-20 for the thermocouple. I still need to drill holes in the corners of the bed, and in a suitable location on the printers main bed platform.

I don't see much of this being completed until the end of next week or early the following week some things have to be completed first. I may be able to work on it each morning for a few min before work each day though.

Once the heated bed is finished I will print a Mendel, I already have the motors, and electronics (I want to upgrade the electronics on this printer) and I may sell the Mendel as a preassembled kit.

Heated Bed

Last night I tried to print a larger part to see how bad my parts would warp... well lets just say that i only let it print about 6 layers before I canceled the print. so later last night I ordered a 1' x 1' x .25" piece of 5052 aluminum, another PID controller since my extruder board is done and 2 flexible 110v 130 watt heaters McMaster-Carr PN: 8009T16.

We will see how this works out, it seams to be a little more simple than it will probably be, but if anything it should at least keep my parts from warping.

If this works well I will look into finding a larger piece of aluminum for my entire print area, If i get that far I will have to work out a way to save electricity when heating that much bed area. I may actually think about heating the inside of the box aswell.

No pics today, I will probably get some up this coming week.