Umbrella ATC - Acorn Compatible

[RJS100]

The goal of this build thread is to build an umbrella ATC that can be controlled with Acorn but requires no additional custom programming (macros or PLC).

Umbrella ATC's can either be driven directly via a stepper motor or via a Geneva cam. While I would prefer to build a direct drive ATC since they are quieter and are mechanical less complicated, others on this forum with more experience than I have indicated that they are more difficult to configure and require custom programming. One advantage of the Geneva cam approach is that it is not controlled by an additional axis.

I will be modifying a plan designed by Alexander Cyr. These plans may be purchased here: https://fabrication-arc.com/collections ... ng-and-cad

These plans cannot be used as is with Acorn so I will be posting the Fusion 360 files for the modification to make it compatible.

The first step to establishing if these plans are compatible with my mill is to compare the fork spacing with the spindle and tool holder details. On the current plan, the fork spacing is 2.82 inches (see below). On my mill the radius of the TTS tool shank (.75"/2) + the spindle diameter = 2.18 inches. Thise leaves .64" of free space so the tool holder shank won't hit the spindle.

https://www.dropbox.com/scl/fi/toe952c5 ... v1sxt&dl=0
https://www.dropbox.com/scl/fi/3e40cjo0 ... jdo63&dl=0


More to follow.

[suntravel]

This is a cool project.

You are a good example that it is possible to build and use your own CNC machine starting from scratch with learning by doing getting more knowledge in every step.

Uwe

[RJS100]

Thanks Uwe. I would not have been able to do some of my project without the help from this Forum and you!

I am equally new to Fusion 360 as I am to machining, but I downloaded a rendering of my mill from GrabCad and modified the critical dimensions and features. I could not do a proper analysis since I need to anchor the ATC before the joints are operable. I need to learn how to do this. I identified two stumbling blocks:

1. The orange box on the left of the mill (see below) is a control box. This must be redesigned and moved upward so it doesn't interfere with the ATC. Unfortunately, this is no easy talk since the spindle encoder is mounted to the top of the box.
2. I am not sure if the forks on the carousel will reach the tools, the forks may need to be lengthened.

https://www.dropbox.com/scl/fi/3f2yw14j ... hkh4m&dl=0

It is unfortunate that I cannot change this ATC from a 10 to 12 tool changer. This would extend the reach a bit. I found another tool changer plan but it is stepper driven (no Geneva cam). This plan is configurable with respect to number of tools. Here is my mill modeled with this 12-tool changer. Looks like a better fit.

https://www.dropbox.com/scl/fi/eiyd286r ... gh8tk&dl=0

I am going to search further for other plans. Please let me know if you know of any.

Thanks... Richard

[RJS100]

Quick question. To make this ATC compatible with the mill I can either make the carousel disk .5" larger in diameter or extend the length of each of the forks. I vote increase the diameter. Any thoughts?

[suntravel]

I vote for diameter, and also would place the control box away from the machine.
Not save to have the hands near a fast moving umbrella .

Uwe

[RJS100]

Thanks Uwe. The buttons on the control box are not used anymore. They were moved earlier. The control box currently houses the valves and relays for the drawbar. I am working on making a smaller control box so this will work out well.

Already increased the carousel diameter by .75". I can't see any negative to increasing the carousel diameter. This gives more margin for error while mounting the ATC.

https://www.dropbox.com/scl/fi/qkfndck5 ... 2apck&dl=0

I am thinking of a designing an arm to mount the umbrella to. I want the bracket to be adjustable in x and y. Since alignment with a TTS tool holder is critical.

[RJS100]

This ATC has a provision for an air blast between tool changes. Does this require custom programming to operate the air blast?

[cncsnw]

Probably not. If the default Acorn umbrella-ATC program and macros do not explicitly support an air-blow solenoid, then you can just wire it in parallel with the tool-unclamp solenoid.

(I assume you are talking about a solenoid for blowing air down through the spindle taper, to clean any chips off the tool-holder tapers as they go into the spindle.)

[RJS100]

Thanks Marc, that sounds like a good solution.

I noticed that there is a "AirBlowNozzle output in the Wizard, but since it is not used as one of the outputs on the ATC schematic, I assume it will not work without further programming.

Thanks again... Richard

[RJS100]

Question on Ether 1616 & Relay module. I have no space in the main part of the enclosure. I don't want to add an additional enclosure if at all possible. It seems like I have space on the door for the Ether1616 & relay modules. Is there any issue associated with mounting them on the door. Please see images of cabinet and proposed location of circuit boards. I don't like the fact that there is a 120V ac line above these boards, but I think it will be ok.

https://www.dropbox.com/scl/fi/y9gic9ed ... p0po1&dl=0

https://www.dropbox.com/scl/fi/qf86ymq3 ... xysfd&dl=0