Current Status on Dallas, Tx Area Lobo CNC

[ski...@verizon.net]

I thought I might post the current status of the Lobo CNC that I received here in the Dallas, Texas area.

A) First, I received my package from Jeff last Friday, May 10, 2013. The unit was well packed and included an inventory/packing checklist. A quick inspection proved everything was in fine order. There were no missing parts and there was no shipping damage or scrapes of any kind.

B) After checking the contents, I set the package aside as a Sunday afternoon assembly project for myself and my teenage granddaughter. I think Jeff has the assembly time pretty well pegged at about 3 - 4 hours because we came in right at 3 1/2 hours. I have an old iMac setup online in the shop so we were able to watch and rewind Jeff's assembly videos as we went and this was a great help.

I have a couple of notes from our assembly experience to pass along.
1) I found that the 10/32 self tapping machine screws were a bit tight for me so I decided early that it was best for me to tap all of the holes as we went. Even though I tapped all of the 10/32 holes, the screws were still a very tight and this made for a very snug assembly. This may have slowed us down a bit but I seriously doubt it.

2) The allen screws in the star couplings that fit onto the motor shafts that I received were a 1.5 mm metric size rather than 1/16" size called out in the video. The two sizes are very close and this could have easily been a part change since the video was made. I would recommend using the 1.5 mm size.

All in all, it was a fun project and everything appears to have gone well.

C) I'm now waiting on the power supply to arrive so I can power the CNC. It should get here any day now. When it does and I'm able to apply power, I'll post an update to my experiences on this thread.

My intention is not to spam the forum but I thought it might be helpful for others to hear yet another person's experience with the Lobo CNC.

Signing off for now....

[Jeff]

Thanks for the status update!  Look forward to hearing how things go once you are fully operational.

-Jeff

[ski...@verizon.net]

I got the power supply in about a week ago. I powered up the CNC and connected the Samsung Laptop that I bought to run the machine and everything came up fine. I worked in all three axes with about 20 passes. I went into the .ini file and shortened the x axis stop a couple of tenths of an inch because with momentum at the highest speed it seemed to run through the stop and slightly kiss the end plate.

I've ordered my starting set of mills. I've received the 1/4" to 1/8" collet adapter and four specialized mills for cutting plastic.

Now I'm just waiting on my Phenolic sheet from A-1 Plastics. I ordered a 2' x 2' section so that I can get multiple pieces including one or two for my tool bed and a couple others for attachment plates.

I do have one question. How is the best way to go about surfacing the phenolic tool bed since it will be about 17 inches long and you can only surface the bed in 10 inch sections? It would seem that if the spindle axis is not perfectly perpendicular with the x and y axes, then clamping and unclamping the material will not necessarily result in a completely aligned and smooth surface.

In summary, everything is working fine and I'm just waiting on my phenolic sheet to arrive.

[Jeff]

There are two ways you could handle leveling the phenolic.  First level the portion that you can reach with an end mill.  Then, you could do one of two things:

1. Shift the phenolic and then machine the normally non-reachable portions 0.010" or 0.015" below level of the reachable portion.  This will make it so that your raw stock can be clamped to the non-reachable region, but for really thin materials, it may put in a slight bow.

2. Incrementally shift the non-reachable portion by, say, about an inch and them machine it flat.  Repeat until you've covered the whole non-reachable area ( in each direction).  The risk here is that rigid raw stock might not sit exactly flush in the center.

Personally, I'd go with the first option because it's simpler, and thin stock will almost always want to warp a little anyway unless it is clamped frequently.

-Jeff

[ski...@verizon.net]

I received my phenolic sheet last week, so I plan to make my main bed plus some additional specialized attachment beds this coming week.

In the meantime, I was able to cut some parts this past week using the manual capabilities of the machine. I had a few plastic boxes that need some custom holes for usb and ethernet connectors and I was able to clamp the boxes in a vise and manually mill the square holes using a special 1/16" dia mill for soft plastic. The holes fit the parts like a glove. I really like the flexibility of this design.

Next time, I'll try to learn some g-code and let the machine do it.

All going well here in Dallas. SIgning off for now....

[ski...@verizon.net]

I took my 2' x 2' x 3/8" sheet of phenolic and cut it into five smaller sections approximately 5 1/2" wide by about 1 1/2' long. I used one of the pieces as a fixed bed for the CNC. I plan to use the others as matching attachment plates to hold tooling.

I bought a piece of 1/4" dia. aluminum rod from my local hardware store and cut four 1/4" dia alignment pins about 5/8" long. I used the DRO of the CNC to drill four precisely aligned holes in the fixed phenolic bed to hold these pins and then drilled the four matching holes in each of the four attachment plates. By using these guide pins, any of the four attachment plates can be removed and precisely reattached to the CNC.

I drilled four additional holes in my fixed bed and threaded these for 10-32. I then drilled out four matching holes in each of the attachment plates sized for the body of a 10-32 screw. Once I place an attachment plate over the alignment pins, I can use four 10-32 screws to hold the attachment plate in place until it needs to be changed.

I built up my first tooling attachment plate to clamp my ABS plastic enclosure cases in place to cut holes for pass through connectors such as USB and RJ-45s. I purchased a small flat machining vise from Lowe's. I covered the jaws with a couple layers of tape to keep them from scratching my enclosures and then I drilled and threaded six 10-32 holes in the attachment plate. My plan was to used six 10-32 screws along with an assortment of washers to clamp the vise to the attachment place. Before tightening the vise in its final position relative to the attachment plate, I clamped a 12" ruled straight edge horizontally in the vise and used it to align the vise to the x-axis by jogging a tool up and down the length of the rule.

Once the vice tooling attachment was complete, I began to investigate which software package that I wanted to use to help me create my gcode. Largely based on Jeff's suggestions, I focused in on CAMBAM. I created a drawing for the opening in an enclosure box, inspected the projected tool path, but I still needed to determine the offset between where my enclosure box zero point was on the drawing and where it would actually be located, machine coordinate-wise, in the vise. This is where I got myself confused regarding the direction of the Y-Axis and how the CAMBAM drawing related to my part orientation. With some guidance from Jeff, I was eventually able to get my mind straight and figure out the proper offset values that I needed. I plugged these values into my CAMBAM drawing, checked the tool path once last time, and then generated my gcode.

I loaded the gcode into the CNC and initially purposely positioned the tool about 1/2" above the enclosure box and reset the Z-axis to 0. It was time for my first gcode dry run. I ran the code and watched the movement of the tool and except for being about 1/2" above the part, everything looked right as far as I could tell. I was now time for the big test. I dropped the Z-axis down to the surface reset the axis to 0 and then backed it up about 1/2 inch. I started up the gcode once again and then watched as the CNC cut my first enclosure using the my gcode. The resulting part was perfect. I'm using a 1/16" single flute mill specifically designed for soft plastics running at the lowest speed on the router and it seems to work pretty well.

I couldn't be happier with my LoboCNC. Jeff, you've made this way too easy. Now I'm busy thinking of all the projects that I could do with this little machine.