Contemplating some upgrades to my CNC Router

[Tool-n-Around]

Nice video’s Kelly, I was wondering how you were getting on a few day’s ago as you keep up a frenetic pace and hadn't posted for a while.

Thanks Dave. I've been using CB quite a bit but when I run into a problem I just figure it out or work around it as opposed to bothering the forum folks. When I build the control system for the new machine, I suspect you could see some questions.

Best,
Kelly

[lloydsp]

Kelly,
Let me ask you a favor to NOT do that when you have problems.  Even if you do solve it yourself, please present your problem and your findings here, so we can all learn from your exercises.

CamBam is so rich with combinations of features that it's hard to know how they all interact all the time.  Some of the features even work differently at different times, depending on the circumstances.

Lloyd

[Bob La Londe]

  YES!!!

Kelly,
Let me ask you a favor to NOT do that when you have problems.  Even if you do solve it yourself, please present your problem and your findings here, so we can all learn from your exercises.

CamBam is so rich with combinations of features that it's hard to know how they all interact all the time.  Some of the features even work differently at different times, depending on the circumstances.

Lloyd

[Tool-n-Around]

Got my Y and Bed beams ground and rail lands machined on the Gantry Beam. The steel bed beams are just 2x4x1/4 & Y Rails 2x8x 1/4. My bud's shop has all kinds of surface grinding equipment. These are by far the straightest things in my shop and could be my primary standard straight edges. I have ground 1/2" MIC 6 plate for the bed surface. I also have 2x4 stock for the legs and plenty of steel for a sturdy base. Guess I'll have to get on with ordering steppers, controller, and building it out. I have a zillion mounting holes to drill and tap for the linear rails.

Best,
Kelly

[lloydsp]

Wow!  That's some NICE stuff.  Be careful drilling!  You only get ONE chance! <grin>
Lloyd

[Tool-n-Around]

I still haven't completed the build for the machine described immediately above. I use my existing machine mostly for machining lost foam casting patterns and occasionally light aluminum work. I don't have the shop space for both machines and I may make the version discussed above a smaller envelope machine dedicated for soft metals. In the meantime I did upgrade my MillRight MegaVee.

Increased Z travel to 6"
Increased height under gantry 6.25"
Conversion from V-wheels to linear bearings on X & Y axis
Conversion from Acme to ball screw on Z-Axis
Improve overall rigidity and accuracy of base/platen

I retained the rack and pinion drive on X & Y and all steppers and the controller.

When all the tariff talk started and before they hit, I bought the linear rails and ball screws. I invested ~$270 into all the linear motion related hardware and an additional $175 for the aluminum tooling plate. Seemed like pretty good value to me. Here's a couple pics and video of the deed.

https://youtu.be/5-XmV04KakE?si=6qxikuRu_Pznt4nE

Best,
Kelly

[dave benson]

Great video Kelly.

I checked here at home and that's a good price for the tooling plate, I thought that I would wait
to see how things turned out tariff wise, what I thought would happen was that the stuff
destined for the US would end up being dumped here and I would end up with a windfall
but this hasn't happened so far.

The only thing that I've noticed, is that there are a plethora of new car and light truck brands which I've never heard of before.

With the new mill in Al I've been using 2 and 3 flute uncoated high helix endmills and running the
two flute dry, I've uploaded a pic of a cut (the ID of a motor mount) the surface turned out nice and the cleanup was a lot easier.
I've left the pic full size so you can zoom in and have a good look.   
                                                                                                                                                                                                                     
The other thing I noticed was that the AL wasn't picking up on the endmill like the coated ones
do where every so often I'd clean with caustic soda, at this point I don't think I'm going to have to do this with the uncoated ones.

Dave

[lloydsp]

I always use an appropriate coolant for the metal being cut -- mist or flood as needed.  It's always flood for deep grooves or pockets.

That's because regardless of the cleanup chore, it extends the edge life of the tools; and good cutters are expensive.

[Tool-n-Around]

I always use an appropriate coolant for the metal being cut -- mist or flood as needed.  It's always flood for deep grooves or pockets. That's because regardless of the cleanup chore, it extends the edge life of the tools; and good cutters are expensive.

Agree, and certainly wouldn’t argue the point, but practically speaking, I don’t think flood is in the cards for this machine though mist is a possibility. It’s just a matter of whether it’s worth the effort for my present level of activity versus hand application. I have a decent knee mill and use that for my more serious metal machining, but it’s manual. No plans to convert it to CNC.

One aggravation here is much of what I machine are my own castings. It’s A356 and I heat treat them, but they can still be a little gummy and are much more prone to tool loading than some of the better wrought alloys. The tooling plate is 7000 series which is also cast alloy for stability. It’s strong and machines well on the continuum of good vs poor, but not as well as the best alloys and can also be prone to tool loading.

Besides the rigidity of this machine, I think the biggest issue here is router vs spindle. I just can’t get the lower spindle speeds with the router and if I could dial it down that far, I doubt it would have adequate speed control or torque. I do have a super PiD controller I’ve been meaning to build, and it claims speeds as low as 5krpm, but even so, for metal cutting, I think I’d be better served buying a real spindle that happily operates in the right speed ranges and just retain/swap the router for foam and soft materials where I need the high spindle speed.

I just am not doing a lot of cnc metal machining at the moment thus why I lament building a dedicated machine, but will probably muddle through with this in the meantime.

With the new mill in Al I've been using 2 and 3 flute uncoated high helix endmills and running the two flute dry, I've uploaded a pic of a cut (the ID of a motor mount) the surface turned out nice and the cleanup was a lot easier. I've left the pic full size so you can zoom in and have a good look.

The .25”D cutter was 3-flute high helix, high polish, carbide. I don’t think the extra flute works for me with the higher speed limitation but I had them. I have seen many suggest single O-flute would be better. I have used them on a few occasions. They seem to cut and clear chips very well but bottom finish is not as nice.

                                                                                                                  The other thing I noticed was that the AL wasn't picking up on the endmill like the coated ones do where every so often I'd clean with caustic soda, at this point I don't think I'm going to have to do this with the uncoated ones.

I have caustic soda (Lye). I also have HCl acid. I’ve been meaning to experiment with either but is this just for carbide clean up? I have read some blurbs that it can attack the cutting edge of HSS and cause hydrogen embrittlement.

Best,
Kelly

[dave benson]

Before I comment I just want to say that the image I uploaded is not the full hi res pic as it was too big 18mb zipped
and when I uploaded it and I had to replace it with a smaller one.

I've included a section of that pic magnified where you can see that I had the chamfer a little slow
but nailed the inner bore. Feed rate and spindle speed wise.

I have caustic soda (Lye). I also have HCl acid. I’ve been meaning to experiment with either but is this just for carbide clean up? I have read some blurbs that it can attack the cutting edge of HSS and cause hydrogen embrittlement.

I've heard this too but don't know enough chemistry to have an informed opinion.
I know it's a thing, but don't know how long the process takes could be hours or days maybe years.

In the first pic is a 8mm four flute cutter that's been used once in 6061 (about half an hour cutting time) you
can see some pickup on the cutter inside flutes and more importantly the relief angle behind the cutting edge.

What I think is happening just before a breakage (if you not going ridiculously fast in the first place) is that the surface finish starts to go off as
material builds up in the relief angle area and closes it down to zero then things go south quickly.

In the other pic is the two flute endmill that produces those good finishes dry.
It's only appropriate for some types of cuts to cut dry, but where I can use it, I do.
 
There is a little build up in the flutes but not much compared to the coated endmill, and more importantly the relief area has
virtually no pickup, I've just ran the cutting edge over my fingernail
and its still very sharp, and I have used it for the Mill and Lathe cnc conversions so it's had quite a few hours of machining time.
Its only ever cut AL.

Dave

[Tool-n-Around]

Before I comment I just want to say that the image I uploaded is not the full hi res pic as it was too big 18mb zipped and when I uploaded it and I had to replace it with a smaller one.......I've included a section of that pic magnified where you can see that I had the chamfer a little slow but nailed the inner bore. Feed rate and spindle speed wise.

I couldn't see as well on the first picture but the section looks very nice. Was it a light full depth finish cut?

What I think is happening just before a breakage (if you not going ridiculously fast in the first place) is that the surface finish starts to go off as material builds up in the relief angle area and closes it down to zero then things go south quickly.

I think it is aggravated by poor chip clearing and like Lloyd mentioned, worsens in deeper holes and grooves for same reason due to all the wiping and smearing. I've seen the same thing cutting plastics like polycarbonate. Just had to experiment with feed/speed and in the case of PC, a little soapy water as lube (I believe as you may have suggested?) did the trick.

When they load, it's usually a disaster........scrapped part and/or broken bit if not watching closely. I've had it happen few times. The cutting sound alerted me and I shut down and was able to save the part by altering my cut plan....but on other occasions not so lucky.

I think I'll try the Lye or HCl clean up on a few HS drill bits. I have to drill holes on my cast  intake manifolds that often 5-10 diameters. Even with a lot of pecking with squirts of cutting flid they still tend to load on the leading edge.

Best,
Kelly

[dave benson]

I couldn't see as well on the first picture, but the section looks very nice. Was it a light full depth finish cut?

Kelly

I don't do the drills, I keep a bit of old hardwood fence post handy and drill into that, roughly
15 mm, it cleans them up and only takes a few seconds.
 
Yes, one of the main things to avoid is re-cutting the chips and this is why CB has a cutwidth
variable which gives room for the chips to be evacuated more easily, this works well but adds
too the tool path length doubling it.

There is some devil in the detail as CB assigns the feedrate to both the profile cut and the stepover
but the stepover cut could be run at full speed as its not plunging or slotting.

In the calcs for the chipload there is a feedrate penalty for slotting and a penalty for plunging.
So spiral milling is the slowest method of cutting out the outer profile.
What I do is drill a hole big enough for the cutter to drop into, set the start point of the mop to that position and no leadin.

This means that there is no plunging going on and you can up the feedrate.
I used for the finish pass, 10% WOC 0.6 mm.

I used a tangent lead in and lead out at full depth.
I used climb milling.

I ran this cutter at 0.022 chip load, I've found this value at first calculating the chip load from the
tool manufacturers catalogue this value is for flood coolant so I took off 20% as per catalogue.
This left me with 0.022  which is what I ran the mop with.

This is the value I run this cutter at always and have had no complaints.
I could run the spindle flat out but the gears rattle about so I use 1592 rpm where the gear noise
quietens down a lot.
I used the plugin to calculate the feedrate for a 24000 rpm spindle using my chipload on the finishing pass.

Dave