Simple one axis controllers?

[Brian Holcombe]

Thanks Dave,

After looking into the costs of the more automated approach I think this simple box is more in-line with the direction I want to go. So, any suggestions on which control box to use?

[Jim Becker]

Brian and I actually spoke about this on the phone yesterday and one thing that came up is the concept of zeroing the tool...a necessary thing for whatever control system ultimately gets used. I know I'd be interested in hearing folks' thoughts about that... Given that the spindle is mounted and will move in the opposite direction that our more typical CNC routers do, what are the best ways to accomplish this task?

[Brian Holcombe]

Jim, after researching the expense of the cnc addition, it looks significant. So, I’m leaning toward the route of simple joystick or push button controller to raise and lower.

I can set RPM’s with the VFD.

Adding cnc capability adds a few thousand to the build that I can do later once I’m prepared to add more capability to the machine as a whole (fence and feeder).

[Mark Bolton]

David's last post sounded like what I would envision. Having to have a laptop at your router table would seem a nuisance. I would think any type of simple controler, arduino, stepper, servo, whatever with DRO at the machine would be the simplest. Some fairly simple setup tools when swapping tools and absolute and incremental would seem to get you miles head. Even a simple DRO on your fence.

[Brian Holcombe]

Alright, starting to get somewhat a feel for what I need here. My plan is to build the Z-axis and I will probably go with a 3/4"-5 ball screw. Looking at roller bearing linear bearings. Not sure where to spec those out at, so I'm thinking two 23mm rails should do it. That puts the pitch, roll and yaw capacities pretty high so that should defeat the deflecting i'm experiencing under higher loads currently.

I want to run off a 20amp circuit, so I'm going to max the power out at around 3kw Probably need around 4-5" of travel.

The motor I'm looking at is a Mechatron 3kw motor which is on a 100mm frame. I can't foresee needing a higher HP motor for that given the hand-feed application. Water cooled as I understand they are quieter than air cooled.

With that, I'm looking at about 20lbs of motor and presumably around 10lbs of brackets/bearings. According to my calculations on moving force, this should be able to move that amount of force.

https://www.mcmaster.com/6627t101

Looking at SRA for DRO's since they offer one with a magnetic tape which I would like to use for the fence. I can have both axis' read out on the same box.

[Malcolm McLeod]

... will move in the opposite direction that our more typical CNC routers do...

I recall from the stepper application I did 1 or 2317-some-odd weeks back, that there was a command for both a CW-home-to-zero-marker (a L/S in my case), and a CCW-home-to-zero-marker. There was even a command to do a high-speed 'search' to the switch, reverse off of it, and finally do a low speed forward to get a precise rising edge of the switch. Probably hopelessly archaic today, but a search of driver commands might yield something similar? I would think you could just use a pushbutton input to command the lift to search in the appropriate direction.

Presumably in Mr. Holcombe's case, any such zero marker/switch would be as low (down) on the Z-axis as possible. ...This hopefully equates to always searching in the 'down' direction? Where 'zero' is in relation to the x-y plane (table top) is irrelevant for the search.

Once it reaches its 'zero/home', you could manually enter a measured/known offset for the specific cutter (especially one with a locator ring on the shank). This now defines how far the cutter (end) is from the x-y plane. Then enter a cut depth (or jog, as the case here may be), lift rises, kick-the-tires, light-the-fires, & we be zoomin'! ...Maybe?

There may be additional options if end-of-travel switches are used (based on the drive selected). It adds to the cost, but I would be hard pressed to not use them in any commercial application.

(I realize this may be initial steps down the path and as I understand it, this IS Mr. Holcombe's profession - - so I'm a bit hesitant to recommend a 'consumer grade' solution. Apologies to those who are making mint with this stuff now, but I'd get laughed at for recommending it and be fired when it smokes with 10 weeks of service at 3AM. Night shift can be REALLY hard on new technology for some odd reason??)

[David Buchhauser]

Alright, starting to get somewhat a feel for what I need here. My plan is to build the Z-axis and I will probably go with a 3/4"-5 ball screw. Looking at roller bearing linear bearings. Not sure where to spec those out at, so I'm thinking two 23mm rails should do it. That puts the pitch, roll and yaw capacities pretty high so that should defeat the deflecting i'm experiencing under higher loads currently.

I want to run off a 20amp circuit, so I'm going to max the power out at around 3kw Probably need around 4-5" of travel.

The motor I'm looking at is a Mechatron 3kw motor which is on a 100mm frame. I can't foresee needing a higher HP motor for that given the hand-feed application. Water cooled as I understand they are quieter than air cooled.

With that, I'm looking at about 20lbs of motor and presumably around 10lbs of brackets/bearings. According to my calculations on moving force, this should be able to move that amount of force.

https://www.mcmaster.com/6627t101

Looking at SRA for DRO's since they offer one with a magnetic tape which I would like to use for the fence. I can have both axis' read out on the same box.

I'm wondering if motorized movement is really the best option here. For example, my Bridgeport has a 2 axis Anilam DRO (x & y) and I have no problem positioning the table to within 0.0005" (according the readout) using the hand wheels. Why would a router lift be any different? Of course I still need to zero the readout to a known position. I could see adding a right angle drive to the lead screw so the operating shaft protrudes from the side of the machine - much like the elevation hand wheel on a table saw (or the knee on my Bridgeport mill). I think the more important thing here is the construction/precision of the lift mechanism, and the actual spindle itself. Depending on how often the router bits are changed (removed/replaced from the spindle) one thing that I would personally consider is using an ATC spindle with interchangeable tool holders. This would mean that as long as a particular cutter/bit is installed into a particular tool holder, it will always be in the same z position (relative to the spindle) when installed back into the spindle nose. Plus - changing the tool holder is about a 5 second operation with this scheme, as opposed to several minutes or more getting out the wrenches, loosening the spindle nut, removing the collet/bit (assuming some of the router bits have different sized shafts), and then reversing this procedure. But much like the computer control, this may be "overkill" for your application.
David

[Brian Holcombe]

Forgive my ignorance in the land of electronics, but I suppose there are no simple controllers which accomplish this and it appears one needs to either go to a CNC program or program one’s own control box? Given how common this application was with positioners I assumed some commercial solutions would be available. Perhaps everyone rather just programs a setup for their own product.

Certainly positioning by hand wheel is fine, it’s something I do for every other machine, but I thought I might chase down the rabbit hole a bit here as I would not mind reducing the number of hand wheels I crank daily.

[Brian Holcombe]

ATC is a nice option but a bit too costly for this project. Looks like it will add about 6-7k to the build, I won’t get return on that for a number of years even though it would be convenient.

[Mark Bolton]

From a total neophyte perspective I think if your looking for dead accuracy or cross referenced positioning (dro/encoder/servo/stepper/with some sort of input interface) Seems like a challenge. Which was why my logic would be simple (not to me) highly adjustable positioning with manual cross referencing to a DRO for manual cross reference.

I think Jim may have been completely on point with being willing to contract/coordinate with Gary as you could likely lop off a bunch of stubbed toes. As per our conversation.. I can learn all the in's and outs of building some foot controlled Arduino positioner, or I can contact a local tech/STEM program that is willing to engineer the whole thing to my desired specifications for a donation to the program. I can choose to be neurotic and need to be the one to come up with the end solution or just sit back and allow a bunch of kids who are way smarter in this regard than I am, have zero pressure of operating a profitable day to day entity, and will get something out of it.

I can only imagine there are a million of them within reach in addition to Gary.

[Brian Holcombe]

I agree, so I gave Gary a call and we're gonna build out a CNC setup. This way I can do the z-axis and Gary can build the electronic systems and control box.

Touch screen to control positioning and rpm on the fly, a system for zeroing and the ability to make fence and feeder a part of the CNC system in the future. Much better than if I try to DIY this aspect of it since I'm pretty far out of my depth in the electronics realm.

[Jim Becker]

I'm looking forward to this project, Brian...'glad you were able to touch bases with "the master"!

[David Buchhauser]

I agree, so I gave Gary a call and we're gonna build out a CNC setup. This way I can do the z-axis and Gary can build the electronic systems and control box.

Touch screen to control positioning and rpm on the fly, a system for zeroing and the ability to make fence and feeder a part of the CNC system in the future. Much better than if I try to DIY this aspect of it since I'm pretty far out of my depth in the electronics realm.

I think you made a wise decision contacting Gary. I believe he is a dealer for Centroid and I expect he will incorporate the Acorn controller (as I had originally suggested) or something very similar in his build. FYI - the 4 hp ATC water cooled spindle I am using can be had with an assortment of NBT30-er25 tool holders/collets for well under $2500, including the VFD and spindle control wiring. I use mine mainly for high speed machining of aluminum, but these work fine with wood as well. The power requirement is 220Vac at 30 amps. I routinely achieve tool run out of +/- 0.0001", so these are very high quality precision tool holders. Not made in Germany, but every bit as good as the Nikken BT35 tool holders I use in my Matsuura.
David

By the way, another advantage of the ATC spindle approach is the ability to store all of your tool presets in the tool table, so no need to re-zero your spindle every time you change out one of your router bits - assuming you leave them in the tool holders and change as an assembly.

Photos were taken before I put the machine into use.
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[Brian Holcombe]

Thanks for the recommendation, I will do my best to afford a German made spindle and if I can afford ATC by one of them I’ll add it to the build. They have a few brands which seem to be quite competitive in pricing and are actually made in house (as far as I know).

[Jim Becker]

Italy's HSD does a huge amount of business in this general size range of spindles...you'll find them on the major USA-made CNC machines like Camaster and ShopSabre.