Well, I'm gathering parts for severalt mods on my phlatprinter so I thought I would might as well start a thread to document them.

The mods I have done so far is to change the Y-stepper to a 1.8Nm (about 260oz.in). I have also done the pressure roller spring mod.

This weekend I changed a couple of light switches at home and thought: Hey, these would work great on my Phlatprinter. With some cable and socket outlets I now have a nice separate powerswitches for the Dremel and and the stepper-driver. Budget for this about $15. Attached files

 

The mods I have waiting in line (within a couple of months) are:

• Belt drive on Y-axis
• Adjustable 12mm precision axles on the Y-axle with 12mm delrin bushings
• Acme threaded rod with delrin ZBN on Z-axis12mm precision axles on Z-axis with 12mm delrin bushingsHome switches on all axes

I have all the parts for these mods, but I'm waiting on the delivery of my micRo CNC mill for making parts with proper tolerances. I have just placed the order for my micRo and I'm really excited to see what it can do! Attached files

 

janbjorn, I think you might do better if you'll get yourself a bigger pulley (on the motor) for the belt mod. A bigger pulley will translate to higher speed.

 

Actually, I've been thinking about finding a smaller set of pulleys than the MK1.5 kit offers.
Larger pulleys mean higher speeds, but lower resolution. At 1600 steps per rev, and almost 4 inches of circumference, 4.000/1600 = 0.0025" or 2 1/2 thousandths per step!
That's why I'm looking for smaller pulleys, and the ones in the photo look about right to me.
janbjorn, Where did you get those? :mrgreen:

 

That's my thought exactly Dorsal. I was looking for the smallest pulleys I could get. I want the speed of belt drive, but I don't want to sacrifice the precision.

I got the pulleys, belt and somee other stuff from here. I spent $35 including shipping to Sweden I have got some bearings and axles for the belt mod as well but that's all. I will make the brackets to mount the stepper and pulley from scrap MDF parts I have at home so my belt mod will cost about $50.

 

:?: :?: janbjorn, could you fix that link in your last post, please? I'm pretty sure you didn't get them from me. :roll:

 

Sorry about that. Cut and paste can be nasty when you're in a hurry. Here is the EBay link to the pulley. Check the sellers shop for belt and other stuff as well. He has good prices on limit switches. I got them cheaper shipped from the US to Sweden rather than going to my local dealer even after paying the swedish VAT on the imported stuff :roll:

 

I was planning on mounting it on the outside, kind of like flash did it. But I will mount both the stepper and the idler pulley outside. I'm on vacation right now, but I'll upload a sketchup drawing when I get back (on sunday)

 

Those are probably the same limit switch I got, because I bought mine from Hubbard CNC, also. They were much more expensive, else where.

 

rjarois, here are som screenshots on how I'm planning on mounting the stepper and pulley for my belt conversion.

As you can see I'm also copying your design on the adjustable rods Attached files

 

That is a sweet looking mod you have got there 3DMON. I'll make shure to verify the attachment point to the gantry. Thanks for posting your pics!

 

Thanks Mark! I hope it will work out OK. I'm still waiting on my micRo though so it will be some time before I can actually implement the belt conversion. However, from seeing 3DMON's conversion using the same pulleys and belt I feel confident going through with this mod.

 

Well, I have not done this mod on my Phlatprinter yet, but I thought I might share it since it probably would work quite well with the MK3.

I used a Turnigy 50-45 890kv motor and replaced the orignal shaft with an ER11 collet chuck

The result is promising so far. I will change the bearings in the motor since I accidentaly damaged them when changing shaft.

A short video when I mill a PCB
Attached files

 

Yes, I really like the sound level on this, and in the video, most of the sound that you hear is from the damaged bearing

Higher kv would really be nice on these motors. At the moment the maximum unloaded rpm is about 10k, so for useful milling I guess 8-9000rpm is the top limit.

I have a 24V power supply that I can use to drive the spindle motor in the future if I see the need for higher speeds (which I probably will). But then I also need to get an other ESC that handles the high voltage so in the meantime I will just clean up the installation and use a 12V PSU instead of the LiPo.

The ESC I use currently is possible to reflash with custom SW and I have thought about modifying that to incorporate closed loop RPM control, but since it has taken me 3 months to build this spindle from when I got the parts, I think the RPM control will take even longer...

 

I'm using a servo tester to control the ESC at the moment. My idea was to continue using the servo tester, but with modified SW the ESC could interpret the servo signal as desired RPM instead.

There is a large thread on flashing TowerPro and other ESC's on RCGroups. Unfortunately the code for flashing the ESC is in assembler, but there is an initiative to convert it to a more user friendly C-code here