[difalkner]

I like your reasoning, Albert. I went with the Hitachi WJ200 - 022SF because it is a far better VFD than the Chinese models and it has far less electrical noise. One thing that I've learned is that Bosch and other companies that tout horsepower ratings for their routers tend to exaggerate their numbers whereas the spindle rating is likely a true(r) number.

My spindle is a 3kW water cooled and yes, it is very quiet and runs very cool. I think the longest job I've run is about 45 minutes and both the spindle and bit were easily handled with bare hands when the job finished. I don't recall the spindle ever getting above just slightly warm.

 

[Albert Z]

Been a few days since my last post. Been extremely busy with work, college visits with my grandson and did I mention that I mentor a teen robotics club. Still I managed to get a little work done on the router.

Finished wiring the VFD electrical panel. The inputs and output wires connect to terminal strips at the top of the panel.

As mentioned in a previous post, the kit did not come with any 30 mm M5 low profile screws. I had to order some and they finally showed up. I finished attaching the wheels to both gantry plates. The bottom wheels are installed with eccentric spacers to permit a tight fit to the rails.

Next I worked on the X-axis gantry front plate by attaching the spacer blocks and 8 mm Acme nut block. I have some concerns about the nut block as it does not seem to be fitting up square to the rest of the plate. I will keep an eye on this and if it becomes a problem I will have to enlarge one of the holes and pin the block to the plate in order to get it into alignment.

I then attached the wheels to the spacer blocks. The wheels on one side are fitted to eccentric spacers for adjustment.

Finally, I have been pondering how to attach the beast of a spindle to the 2060 V-slot carriage. As you can see from the photo, the mounting bracket base is much wider than the 2060 Z-axis V slot. My solution is to manufacture a carrier plate that can be bolted securely to the 2060 with extensions at one end to accommodate the M8 spindle bracket mounting bolts. The carrier plate would be attached with eight M5 screws.

I ordered a 3/16" thick sheet of T6061 aluminum 12" x 12". I drew up the carrier plate in AutoCad from measurements taken from the spindle mounting bracket and the 2060 carrier rail. When my aluminum plate shows up, I'll cut out the part on the robotics club CNC router.

Last night while fitting all the pieces together I realized that the overhang from the spindle mounting bracket is going to interfere with the V-wheel mounting bolts thus restricting the amount of Z-axis travel to about 3". I would like at least 4" of travel and preferably 5" depending on the height of the spoiler board. As the build progresses I will make a determination of exactly how much Z-travel is available. At that point I may opt to buy a longer 2060 carrier and lead screw (250 mm). We shall see as we progress.

 

[Albert Z]

Some Thoughts on Spindle Mounting

If we go back and look at my first post, I attached a stock photo of a complete OX-CNC Router. I you look closely at the photo you can see clearly that the V-rail for the Z-axis is supported by four rollers. Because of the heavy overhung load due to the heavy spindle and mount, it would be highly desirable to have the extra rigidity provided by the fourth roller.

This would seem on the surface to be a straightforward modification. Simply replace the existing 3-hole spacer block with a 4-hole spacer block, add an extra pair of wheels and Bob’s your uncle. Hold on! Not so fast my friends. This is turning out to be a bit more of a slog than I first supposed.

Based on the stock photo showing four rollers, one would think that a 4-hole spacer block would be readily available from one of the on-line suppliers of OX kits. Such is not the case! I have scoured the internet looking for a 4-hole spacer block and have come up with zilch – nada. Oh, there are lots of 3-hole spacer blocks to be had, but no 4-hole, at least not that I have been able to come up with.

The next avenue I explored was making my own 4-hole spacer blocks. The original spacer blocks that came with the kit were fabricated from 12mm x 20mm anodized aluminum. This size is not readily available, at least in small quantities so I opted for ½” x ¾” aluminum stock which is easily obtained at fairly low cost. I drew up the part in AutoCad but ran into another snag. The eccentric adjustment spacer is a precision fit into a 7.13mm hole which is not a standard drill size. Grainger offers a 7.13mm reamer at the bargain price of $176.00. What I don’t want is a loose fit on the eccentric; otherwise I would be better off with no fourth wheel. So that essentially kills the idea of manufacturing my own spacer blocks.

So, how to get that fourth wheel installed without breaking the bank and re-designing the Z-axis? My solution is to buy a 3-hole spacer block, saw off each end and mount it to the X-axis plate above the existing 3-hole spacer block. This way I would only have to drill a pair of holes in the X-axis plate to accommodate the 5mm fixing screws. See the attached drawing for details.

So in order to make these mods I ordered a pair of wheel assemblies, a spacer block, some ¼” spacers, a pair of eccentric spacers and hardware for installation. While at it I also ordered an anti-backlash nut block to replace the one that came with the kit. So now we wait.

Electrical Cabinet

Meanwhile, I got started on the electrical cabinet by installing the exhaust outlets at the top of the cabinet and the fans in the bottom of the cabinet. The fiberglass reinforced plastic is tough as hell on saw blades. Completely destroyed two blades cutting the holes for the inlet and outlet.

 

[jw2170]

Great to see how this build is progressing, Albert.

 

[Albert Z]

Not much going on in the shop these past few days. Been working on the electrical panel layout and component placement. This will determine where to put the penetrations for the cables to the stepper motors and limit switches.
Referring to the attached drawing (sorry if it’s cocked a little), the toroid transformer, 10,000uF capacitor and 50 amp full wave bridge comprise the 36 volt power supply. The transformer is double wound with each winding rated at 7.5 amps. I am wiring them in parallel to increase the overall capacity to 15 amps.

In the upper right hand corner are the auxiliary power supplies. There is a 24 volt power supply dedicated to the RMHV3.1, another 24 volt supply for the contactor coil located on the VFD panel and a 12 volt supply for the fans. These are DIN rail power supplies and take up very little room in the cabinet. (See photo).

I used conventional terminal strips for the 36 volt DC and 110 volt AC distribution.

For the control wiring I decided to use DIN rail terminal blocks. These are quite convenient to use since all you have to do is strip the end of the wire, insert and snap shut for a solid connection. The ID for each terminal block corresponds to one of the wires coming from the DB25 connector except for the 24 volt RMHV3.1 power which goes directly to the DIN mounted power supply. In the process of laying out the connections for the terminal block, I realized I forgot to include the separate 12 volt supply and ground connections for the probe and limit switches. I will have to go back into the control box and add these.

Happy Thanksgiving everyone and thanks for watching my thread.

 

[Albert Z]

Continuing on from my previous post, I have spent quite a few hours working on this project with not a lot to show for it. Nevertheless I have been soldiering on with most of the time spent on mounting the electrical components to the sub-plate which will get installed in the electrical cabinet. A good bit of time was spent putting labels on all the terminals. In addition, I installed the DB25 connector into the side of the electrical cabinet as well as the 4 connectors for the stepper motors.

I got tired of waiting for the spacer block that I was going to partition (see post #23) so I took one of the existing spacer blocks and cut it up in order to prove the concept. Seems to work pretty well - now I just need the other spacer block to finish the Z-plate assembly.

How are we doing with the budget?

Way back in post #1 I estimated the cost of this project to be $2000. Every project manager has to track expenses vs. budget so this is where we stand to date:

OX CNC kit $514.86
CNC Controller $291.50
Electrical Cabinet $143.99
Spindle & Accessories $262.99
Stepper Drivers $ 84.76
Misc. Elec. & Mech. parts $396.97

Total Spending $1695.07

 

[jw2170]

I like following your posts, but starting to get a bit too technical for this old brain.... LOL