BOSS 9 Retrofit - Verispeed question

[dirtdiggler]

Hey Guys,

I recently finished a restoration and retrofit of a Boss 9 series II CNC. It was almost a year in the making but I'm finally off milling stuff with it.

I'm running Mach III, Larken Vipers 200's, C23 board and a smooth stepper. I also hooked up a VFD to run the spindle with 220V. The machine is pretty darn fast, much faster than the servos can handle so I had to slow it down.

The last thing I have left to do is sync my VFD with Mach, and figure out how to adjust the the varispeed/shives with my BOB. To control the speed currently I just manually turn my VFD to the disired speed.

My question is: Do I loose any milling capability by using only the VFD to control the speed? Do I need to even use the verispeed?

I mill mostly Aluminum 6061 and Nylon plastic.

If so, is there recomended position to put the shives in while in conjunction with the VFD? I'm not familiar at all with how the shives effect the speed and torque on this beast.

Also, what was use of the bull gear on these machines? When I engage it, it slows the speed way down, if I engage in the other direction it reverses the spindle direction. I haven't figured out what use there is for this yet.

Anyone out there with experience retrofiting VFD's onto these I would greatly appreciate some of your advice on this.


Cheers

[gschoep]

Do your pulleys still look that dirty/rusty? (cant tell which in the picture)

My head is making a racket so I opened it up after seeing the picture that you posted. I have dirt and dust but the pulleys are shiny metal.

There are a couple threads on here that talk about setting the VFD at a constant rate and using the speed adjust and vice versa.

According to one post there is a sweet spot that people set their speed to in the VFD.

Another post suggested that you disable the variable speed (set it to 1:1) and use the VFD only.

[TOTALLYRC]

Originally Posted by dirtdiggler Hey Guys, I recently finished a restoration and retrofit of a Boss 9 series II CNC. It was almost a year in the making but I'm finally off milling stuff with it. I'm running Mach III, Larken Vipers 200's, C23 board and a smooth stepper. I also hooked up a VFD to run the spindle with 220V. The machine is pretty darn fast, much faster than the servos can handle so I had to slow it down. The last thing I have left to do is sync my VFD with Mach, and figure out how to adjust the the varispeed/shives with my BOB. To control the speed currently I just manually turn my VFD to the disired speed. My question is: Do I loose any milling capability by using only the VFD to control the speed? Do I need to even use the verispeed? I mill mostly Aluminum 6061 and Nylon plastic. If so, is there recomended position to put the shives in while in conjunction with the VFD? I'm not familiar at all with how the shives effect the speed and torque on this beast. Also, what was use of the bull gear on these machines? When I engage it, it slows the speed way down, if I engage in the other direction it reverses the spindle direction. I haven't figured out what use there is for this yet. Anyone out there with experience retrofiting VFD's onto these I would greatly appreciate some of your advice on this. Cheers

Hi Dirt,
Without starting a huge controversy, my mill, a BTC-1 has a similar head but doesn’t use the vari-speed. It just has timing belts. It is set up from the factory to give 5k rpm at 60 hertz in high gear. It also has a 3hp motor.

The other gearing is for low speed uses such a tapping or heavy cutting.

On mine I have not yet had to shift into low gear. I am currently doing mostly aluminum. I am using a Sensorless vector drive which gives full torque all the way down to ~1 Hz

I plan on integrating the high/low shifting into the control, but right now it is on the back burner since it isn't a big problem to do by hand if I need to do so.

In your case, since you are doing mostly aluminum, I would use the VFD to control the spindle speed and put the varispeed where you are most happy with it. If you need to you could adjust the varispeed when and if the need arises. The VFD can be easily controlled by Mach3.

Mike

[mactec54]

Hi dirtdiggler

Have a look at my photos in the Gallery you will see how I did it on a Boss Head I made new parts & a 1/1 drive it has a air disc brake all operated through the control your motor is able to run at 120HZ which can give you 6,000 rpm you will need to have the motor balanced for that this last one that I did has more then 8years on it the belt is only .625 wide poly-v-belt
I have done many of these Boss heads & machines this way the photo below is not the same belt that I use mine has 6 ribs
These are the best you could use

[dirtdiggler]

Originally Posted by gschoep Do your pulleys still look that dirty/rusty? (cant tell which in the picture) My head is making a racket so I opened it up after seeing the picture that you posted. I have dirt and dust but the pulleys are shiny metal. There are a couple threads on here that talk about setting the VFD at a constant rate and using the speed adjust and vice versa. According to one post there is a sweet spot that people set their speed to in the VFD. Another post suggested that you disable the variable speed (set it to 1:1) and use the VFD only.

Hi gschoep,

Thanks for the great info.

Yes those pulleys were rusty and nasty. The picture was taken right when I got the machine, and it hadn't turned on in years. I had to lightly sand the surface of both pulleys with steel wool to get them smooth again.

It's funny you talk about rattling because I get some rattling up there now as well when I'm running the spindle at certain speeds. I'm trying to figure out what's causing it. It sounds like it could be something to do with my spindle bearings....no clue how to trouble shoot this. I hasn't become a major issue yet.

[dirtdiggler]

Originally Posted by TOTALLYRC Hi Dirt, Without starting a huge controversy, my mill, a BTC-1 has a similar head but doesn’t use the vari-speed. It just has timing belts. It is set up from the factory to give 5k rpm at 60 hertz in high gear. It also has a 3hp motor. The other gearing is for low speed uses such a tapping or heavy cutting. Mike

Hi Mike,

Thanks for your help.

Another question for you: How do you measure spindle speed without a tachometer? Is there an inexpensive DIY trick for measuring spindle speed or do I need to get my hands on a tach?

BTW, your retrofit build post is excellent.

[dirtdiggler]

Originally Posted by mactec54 Hi dirtdiggler Have a look at my photos in the Gallery you will see how I did it on a Boss Head I made new parts & a 1/1 drive it has a air disc brake all operated through the control your motor is able to run at 120HZ which can give you 6,000 rpm you will need to have the motor balanced for that this last one that I did has more then 8years on it the belt is only .625 wide poly-v-belt I have done many of these Boss heads & machines this way the photo below is not the same belt that I use mine has 6 ribs These are the best you could use

Very cool and nice work. I saw one of your images here: http://www.cnczone.com/gallery/showp...52/ppuser/8005

I like how clean that system is. I think my series II Boss9 head is a bit different, From your picture my head looks to be bigger in size and I already have an air break built in. I like how your getting 6K with a direct drive though.

What do you mean by 'balance the motor'? Is that to avoid spindle vibrations?

Can you cut hard metals with 6K RPM... or do you mostly cut aluminum?


Thanks

[TOTALLYRC]

Originally Posted by dirtdiggler Hi Mike, Thanks for your help. Another question for you: How do you measure spindle speed without a tachometer? Is there an inexpensive DIY trick for measuring spindle speed or do I need to get my hands on a tach? BTW, your retrofit build post is excellent.

Thanks for the kind words.
Mach3 can display the rpm right on the computer screen.

http://www.machsupport.com/docs/Mach...all_Config.pdf

section 4.11 and 5.3.2 tells a little about it. Basically you connect a once per revolution sensor and then hook it up to the index input and it will display the rpm on the screen. You will have to set up the gearing on the pulley page if you hook the sensor to the motor shaft. if you can put the sensor on the spindle then of course it will always read out in spindle rpm.

Mike

[mactec54]

Hi dirtdiggler

Yes my head is different I took 5" out of the top of the head so it looks realy different from yours but every thing inside was the same as your one

To balance the motor you have to take it apart & the rotor has to be balanced it is so it does not fly apart at 6,000rpm you need good bearings in the motor as well you won't be able to run your head at high rpm untill you get the vari-speed removed & a 1/1 drive in there

The rattling you are getting is coming from the vari-speed pulleys that have bushings in them they will be warn out

& for hard milling you need 40,000 to 60,000 to get it done

[dirtdiggler]

That seems like some serious speed to cut hard metals. What are you able to cut at 6K RPM... just Aluminum?

Originally Posted by mactec54 for hard milling you need 40,000 to 60,000 to get it done

[dirtdiggler]

Hi Guys,

I've been fooling around with my air selnoids today trying to get the verispeed to adjust and I'm having a difficult time which is making me think it might be better to take some links off the chain to adjust the shives closer together (maybe halfway) and then do the fine tunning with the VFD.

Does anyone know how many positions the veri speed had originally?

I have a Teco 7300 3HP that I'm using for the 2HP motor. Is there anything I should know as far as how much I can push the motor with the VFD?

I've been running it mostly around 50hz cutting aluminum with no issues.

Thanks-