ATC for the Bridgeport mill

[Derek]

So being as I used the ATC on it’s first paying job I figured it would be a good time to show everyone what Terry and I have been up to.

Some history. I made an ATC for my Alliant mill many years ago and it’s been working like a champ ever since. It’s a traditional style rotating carousel where the entire carousel. moves.

I wanted an ATC for my Bridgeport and started making the parts. It was going to be exactly the same as The Alliant except it would hold 12 tools instead of 10. As I was machining a batch of my cylinder heads, manually changing tools, I realized that the ATC I had started on wasn’t going to be the best choice. That’s when I started thinking up the current changer which is basically a hand grabbing a tool and putting it in the spindle.

Terry was already working on the macro for the 12 place carousel changer and he and I started hashing out different ideas. I wanted to incorporate as much of the stuff I had made already and started cruising ebay for the rest. Everything went a lot smoother than I expected and most of the systems worked on the first revision.

The drawbar is based on Ray Livingstons stepper drawbar design. I've been using it for a few years now.It is kind of slow and I have plans on upgrading that as well as incorporating a torque sensing plate to really verify that it is tight. Currently we monitor the RPMs of the drawbar figuring when the drawbar stops turning it is tight. There are scenarios where I could see the stepper stalling before the tool is tight and a torque sensor would solve that.

All of the ATC sensors and outputs are being handled with a CNCroom UD1-U and has been working flawlessly. So far I have around 500 tool changes with it and I really couldn’t be happier with the dependability.

[Derek]

I guess you tube embedding is broken. It worked in preview. Follow Terry's link

[Robertspark]

Hats off to you both that was or appears very complex to work out the geometry

[andrewbishop66]

Can I just ask how the knee is driven I have a similar conversion but the spindle is raised up and down so limited z travel

Thanks Andrew

[Derek]

The bridgeport has a ball screw with a rotating nut and air assist. The Alliant just has a servo slapped onto the knee lift screw and air assist. I have 4:1 on the Alliant and it's been working for years and years.

Terry knows someone who is using the quill for the Z and the knee for tool offset positioning.

[andrewbishop66]

Thanks for that

andrew

[cncdrive]

Andrew,

We make BF50 CNCs with similar construction as the Bridgeport.
What we use to lift the table is a 90° precise gearbox, I think it is made my Neugart and is not too cheap, in the 1000-1200 Euros price range if I recall, but it worth it's cost and a large ballscrew is driving the knee up and down. The upper Z axis we keep manual adjustable.
I'm adding some photos to this post.

[Derek]

Is the gearbox up in the knee turning the ball screw?

Can you post the part number of the gearbox you are using? Eventually the Alliant is going to crap out and the system I have on the Bridgeport works well but it was a lot of work to produce.
The system you are using looks really nice.

Derek

[cncdrive]

Hi Derek,

You can see it better on the attached picture.
I can't find an order email wit hthe type number now, my collegue used to order these, so I can ask next week.
But I found a drawing from Neugart, please check the attached pdf.

[cncdrive]

And if you will order one of these or similar then order it from the French Neugart.
The company, the manufacturer is German, the French are just their distributors in France, but the Germans give far higher quotes is what we learnt.