Here are some of the mods I did to my PhlatPrinter. These were originally posted on RCGroups but thought I would bring them over here so they would be easier to find.

I did a mod on the drive roller because I was not sure how long it would last just having the two drywall screws screwed into the thin plastic cap. Even though the drive pulley was glued around the edges I still wasn’t sure. What I did was cut a 3” dia. wooden disk and glued the plastic cap and the disk to the drive pipe then glued the pulley to the pipe and inserted the screws through the cap into the wooden disk. This won’t be going anywhere.

I really wanted to be able to service all aspects without having to destroy something in order to get at it. To start, even though it was not necessary, I used precision ground harden drill rod for all the rods. I ran into the same problem that others have posted about concerning the movement of the Z axis. Not wanting to elongate the holes that the rods sit in, I chose a different approach. I made this modification to the Y and Z gantries and feel is well worth the effort. The mod involves installing sleeve bearings in place of the pex pipe. What this accomplished was absolutely no slop and extremely free movement. The mod is fairly easy but does require some modification to the holes. Especially on the Z-Gantry since those holes are offset from the top and bottom holes for the rods. The Y gantry was easier. The top holes of the Y-gantry needed no modifications but the bottom holes required removing a little material toward the top of the hole to allow perfect alignment.

The sleeve bearings that are listed below are a perfect fit. What I did was as follows..... I used a mill (a drill press would be good too) to do make sure that when I made the z-gantry holes bigger that they would line up the centers. Center of holes should be .7" from side edge and .8" from top edge. It ended up taking a little material off the outside edges of the two top and bottom holes. I then counter-sunk a larger diameter hole so that the flange of the sleeve bearing would sit flush. I used JB weld quick set glue to glue the bearings in place. Once I applied the JB Weld I installed the bearings and then mounted the Z-gantry to make sure that the bearings could find their centers with the guide rods before the glue completly set up. I did the same thing with the Y-gantry. As stated above the top holes required nothing but the bottom holes needed some slotting. I used a dremel for this. The bearings were a loose fit because they could move up and down. Again I applied the JB Weld and then mounted the Y-gantry in the printer and let the bearings find their centers on the rods and then waited for the glue to dry.


McMaster Carr Sleeve Bearing Part # - 6338K466

I wanted to be able to remove the Z gantry carriage if I ever need to (and I have a few times now). The problem was that once part # 9 gets glued on, the rods can no longer be removed thus not allowing the carriage to be removed. My solution was to drill holes in part #9 that would allow the rods to slide up through the top. I then used a little sho-goo to seal the hole and keep the rods in place as they were intended. This stuff can be easily pulled away if necessary, but holds strong. I also drilled a hole in part #9 so that the lead screw could also be removed through the top. I did not like the idea of the lead screw just rotating in the hole. I felt that over time the threads on the rod would wear into the wood and eventually elongate the hole and make it sloppy. So I drilled the hole to a 3/8 and inserted a 1/4 x 3/8 bronze bushing. The one I used had a flange on it so I recessed the area it would sit against on part #9. I used the same size bushing to do the same thing for the Y axis lead screw. One other thing I did to the Z-gantry was to use T-nuts on the stepper mounting holes. I can now remove the stepper very easily if I need to replace it.


I made provisions to allow the side plates to be screwed on so that the stepper motors can be removed with ease. I am also doing this on the top just in case I ever need to have complete access to the upper end. I used 3/4" angle aluminum and used machine screws to secure the top. Will add pic later.
To be able to get at the bolts that hold the X and Y steppers, I cut notches in the back plate that are directly in line with the bolts. This allows a screwdriver to easily reach the head of the bolts.

Once the carriage was mounted I noticed that it would be very difficult to access the nuts on the U-bolts if/when the dremel needed to be replaced. What I did there was drill 4 holes in the back plate spaced to correspond to the U-bolt bolt pattern.


A mod I did to the lid so that the rollers could be taken out and serviced (replace skid tape) easily was to drill two holes in the outer side plate. I used wooden plugs to fill the hole and made sure they sat flush to the inside so that the rods would not catch on the lip of the hole if they went up that far.
This mod is not really necessary as one could certainly drill a hole in the slot once the lid is built if they would need to remove the roller. However, I figured I would do it now so I would not have to worry about it in the future.

I also attached a small cable connected to the side of the lid and the side of the printer to keep the lid from extending back to far and stressing the hinges

I upgraded the Y and Z axis stepper motors to these JVL MST001A ( http://jvl.dk/files/pdf/ld052gb.pdf )
These were a direct replacement. The only thing I did was increase the voltage reference a little. The spec on these are 2.5 Amp. Which means that I would need to increase the VR to 5 volts to achieve the maximum amp draw. However, I only had to set it to 2.8 volts ( which was setting the arrow to the 12:00 position on my board) and it runs just fine. Heat sinks are still very cool to the touch

 

A few more mods that I have done to mine that have really helped were some that Randy (rjarois) and a few others that posted.

I added an adjustable fence by using some aluminum track rail and mounted it to the front of the printer. I then machined two aluminum bars so that it would slide in the track. put a bolt with a washer through it and I can lock it down anywhere I want. The table then mounts to the front of the track. I'm currently using velco to hold it in place and that seems to be working great.


I upgraded to 3/8 4 start acme rod on the Y and Z axis. The speeds are much better now. I've been cutting at 275 ipm without issues. So far when I go much higher than that I've had some issues with it missing steps. But the speeds I'm getting are more than enough for me.




Another mod that Randy did that I really liked was making a block to adjust the y axis rods so that they run perfectly true.



I also did the pressure roller spring mod. I did it to both the front and rear roller and it really seems to help with the wavy foam.

Lastly, I added a 24" small diameter fluorescent light to the lid.

I can't find my photos of the last two mods above but will take some more pics and post them later.

 

Thanks for the comments Randy. Yeah I knew you had gone to bigger steppers. I may eventually do that too. The ones I have are 169 in.oz. Right now I'm pretty satisfied with their performance but may go bigger in the future.