24 v power supply I purchased for the control circuits.
The Bidgeport Boss 5 is ready to try
It always sounds easier than it really is. This retrofit took about 5 months to do. I worked on it some every week. Sometimes 6 or 8 hours a day.
I have a good 40 hours just getting it clean and painted.I gave it a good bath. It had years of chips, oils, and coolent caked on it. Wire brushes, sanders, sandpaper, and a lot of work shined it up good. Then a good coat of paint. I removed the cabinet to get them clean and painted.
I recommend gutting the whole machine. I did it slowly, thinking I might save some wiring etc. I ended up gutting the whole thing. I would have saved a lot of time just gutting it to start with. I did use the control switches on the face of the machine, contactors, the overload relay, the disconnect, fuses, and the 120 v transformer. I powered the fan, and the 24 v power supply from the 120 v transformer.
I spent a lot of time with the stepper drivers, and understanding the original stepper motors. The big thing was realizing that they are slow. Once I slowed them down, and seperated the power supplies, things started to move forward.
Mach3 motor tuning needed to be set in the 20 to 30 ipm range. They ran pretty smoothe there. I am told that the motors need more than the 24 volts I am using. I will try 48 volts or better as time goes on. I understand that closer to 80 volts gives better speeds. Some say not so. We will find out later on.
There were other issues with this machine. The bushings were bad in the pulleys for the variable speed assembly. Someone had taken it apart. It was missing some parts. I was able to get the replacement bushings and the large spring, from a Bridgeport dealer. I had to make a couple smaller bushings.
It had a short in the speed control solenoid. It is 24 volt operated. On top of tracking that down. Someone had taken apart the air motor for the speed controller. It was assembled wrong, The vanes were pinching a fiber ring, The vanes were rubbed down on the ends. This allowed a lot of air to bypass. It would not turn the speed control. I found the air motor Bridgeport used is still available from the mfg, GAST inc. I aquired a rebuild kit from them. Now it works great.
It ends up the motor in the Bijur oiler was bad, It had a couple teeth missing in the reduction gear. Bijur still has them available. They are quite spendy.$108.00 ouch. The lube pump is not much good without it.
I modified the control panel arm to make it a monitor and keyboard mount. This turned out real nice. I can swing it out of the way.
I kept both the very large electrical boxes. I have the fans working in them. It left a lot of room to keep the computer out of harms way, and to service or change anything.
I added a piano hinge to the large door on the computer cabinet. That made it easy to access the new computer, and stepper drivers. I may change the steps in the future, or change the current limits.
I used a optical isolated break out board. Trying to avoid problems. I had to get a 5 v power supply for the breakout board, and for the stepper drivers.
I started with Longs stepper drivers. I still have one. One quit working. They would replace it if I paid freight both ways. It was cheaper to buy a new one. I still had issues with them shutting down as I raised the current limit. And the limits were still under 2 amps. So I replaced the x and y steppers with an inexpensive units I bought from Hubbard cnc on ebay. They work great. But they are limited to 4 amps, and 40 volts. So in time I will change them. I am hoping the longs drivers will work better at highter voltage. If not I might make a router table with them or something.
I tried replacing the original steppers with some longs motor co steppers. After a lot of trial and error, I was able to get the stock motors to work well. I am running them 1/2 step. So I have some extra motors to play with. Maybe the router?
01-18-2011
I finally recieved the new power supplies. I have 48 volt power supplies in my machine now. What a difference now. I have rapids of 80 to 90 ipm, lot better than 20 to 30 at 24 volts.
The 2 drivers that were working good, that I got from Hubbard cnc, were rated 40 volts. They did not like 42 volts. ( 42 volts was the min I could set the new power supply for.)
I put the first set of drivers I got ( the chinese ones that would not stay on) back in. They love the higher voltage. They do not drop out now, they opperate smoothe. They work the original Boss stepper motors great. The ones I bought are only 5.8 amps. I have them set to max. I have the drivers set at half step, works great. I will get into some serious machining soon. Then we will see the true capabilities of the retrofit.
Also recieved the home switches for the machine. I am going to get those installed soon. I will appreciate these.
