Stop Slotting the Stupid Way! Use High Speed Machining! Widget26 

Just one thing. There is no reason to conventional cut with cnc on metal. Climb milling is advantageous on all metals when you have near zero backlash. Some plastics like things a certain way, but climb milling keeps the sharp edge boring through the worked material or into fresh material and bigger oversteps are best, the more overstep the closer to perpendicular the motion of the edge vs the surface of the material. Conventional milling puts that blade almost tangent to the last flute. The circular path you are using helps chip removal. If you can get the circles counter clockwise and kill the extra path I think you can get the ipm up to 30-80ipm in one pass depending on coolant and how many rpm the spindle can handle.

If only slotting was the only thing I did "the stupid way." :)

This is a little behind the release date but still relevant: I migrated from cam-operated screw machines to CNC lathes and much of the methodology and techniques worked well for me. There was a very big eye opening job however that changed the way I looked at the CNC world. The simple job involved turning, drilling and cutting-off of 1 inch round 304 stainless steel. In the screw machine world cutting off is a slow feed operation. When I attempted the technique on the CNC lathe the cut-off (a coated carbide insert) tool would only last 8 parts. I was running, IIRC, about 1000 rpms and feeding about .002 IPR…. A call to the tool company solved the problem. They recommended 3200 rpm @ .006 to .010 IPR. Okay… whatever you say… I was prepared for flames and molten steel. Well SOB!! It worked! And it worked *very* well. Tool life went up to 300 pcs per insert from 8, the surface finish was amazingly good, burrs went away and dimensional consistency never was a problem again. The moral of the story is that you can run too slow. Running slow causes all kinds of problems. BTW… 5100 rpm on a 1/4 inch carbide end mill is too slow….if your mill has 10,000 rpms you should be there. That's only 650 fpm. Remember, your cutting aluminum. Go fast!

Nice John! I suppose we are the RU-vid self-taught new generation of do it yourselfers. We are learning from each other at twice the speed though. All we need is for someone to share good content, and folks like yourself are serving this community well. I thank you.

A few thoughts, in no particular order: 1) That tool path is call Trochoidal Milling, just FYI. Using the proper name instead of HSM style will keep the nomenclature nazis off your back for a while. ;-) 2) You're getting chip welding almost certainly because you are conventional milling that tool path. Switch to climb milling and maybe up the % lube in your air and that problem will very likely go away. 3) You own a manual Bridgeport Series I milling machine, yes? If so, you ought to be running a job like this on that thing so that the CNC can spend it's spindle time earning the top shelf bank. (IE put the longer cycle time and/or higher paying jobs on the CNC and let it eat while you bang out simple stuff like that slotted piece on your manual mill). Excluding setup time (which will be near identical on either machine), you should be able to rough and clean up that slot to size in that part in less than two minutes on your manual machine. I know I could do that, which means you can too. You're where I was back in ~2005 in that you still use your CNC to do work that is more profitably done on a cheaper/simpler manual machine, because you doubt your abilities with the manual machine tools. Don't doubt yourself, embrace the manual machines. They are the key to increasing your shop's throughput without adding any new spindles. The trick is to keep the CNC running long cycle time programs by either gang fixturing simple-ish parts or saving the CNC for the parts with more complex geometry. Then you can load the CNC, hit the GO button and let it work unattended while you do the simpler work on a manual machine. There's no reason to spend the time to make two or three programs and change tools around in the CNC to make a few rectangular parts with a slot down the middle and three or four holes in one side. That's something that can easily be done manually on your Bridgeport while the CNC is running a more complex (and therefore more expensive) part. The more you use your manual machines, the more useful and time efficient you'll find them, and the more profitable you'll find your shop.

John- I have been a CNC Machinist and Programmer for almost 25 years and have worked at many different shops, in short the biggest thing that happens when you work in a bunch of shops is that your horizons expand and you learn what is possible.

with that tool path you should climbmill it will allow the chips to clear better and wont have cutter deflection into the walls. great video! we climbmill all tricoidal movements

+1 on climb milling. I never conventional mill on my CNC. Only time you conventional mill is on the Bridgeport so the workpiece doesn't get jerked around due to backlash.

Well done John,.. Keep us up to date with it.. I always have terrible moments when i have to slot the first pass in pockets for every height in it.. the tool noise and the vibration is so scary.

Thanks John. It is always good to see new ways to go about "common" tasks.

man you are awesome, thank you for sharing your content, im going to start a CNC course next week and i had my doubts about it, since im "stepping down" from a more "lucrative" job ( pharmacy ) but im doing it for pure passion for creating stuff, you are such an inspiration and again thank you for sharing

It's cool to see the evolution in your processes, I'm glad it works for you. In our shop we would have done it different. But then again we have Fadals. Often we try every method until we find the fastest. Keep up the good work with the videos I love seeing your lathe work. Having run a hyundai for years I'd love to get one of the tormac models for my home shop. Also as far as machinist go you could ask 10 different people and get 10 different answers. It's whatever works best for you at the time.

Hi John, In conventional, we do a move that I call rocking the Y axis, a little like the circular motion you give your machine, really makes a difference on chip load and speed. I know I'm still and probably will die conventional... lol Thanks for time you spend doing this, Pierre

This speed up of cuts is nothing but beneficial and I think you could go even faster with coolant. Thanks for sharing! :)

This video is a game changer for me, I have a homebuilt CNC router using a zipsaw and I can cut 1/2" deep through hardwood using the HSM pattern in a single pass! It took me a bit to find that option in my cam program, but I can't believe how well it works. I love the idea that it's working the whole tool instead of just wearing out the tip. Great videos!!

really enjoy your vids. wish I could use fusion like you use it. can you work with a 3D dwg wire frame? if so I may have some work for you.

Awesome. Perfect timing. I need to make some soft jaws for cutting down some little machine screws, and need to make a slot that's just under 1/8". I needed to get some 1/16" end mills for another project, maybe I'lll do that and try out some high speed machining!

You sure have come a long way and learned a lot since this John.

I love that shot at the end when you've got the Tormach behind you and the venerable old Bridgeport over to the side.

Great job experimenting and learning something new!

I just started a knew job running a milling machine. My question is what's the best way to find the center of a shaft to make a keyway? Thanks

What your looking to do here is trocodial milling the trick is to have the tool constantly engaged onto the job works a treat as long as the machine has the power and the ball screws are up to it any backlash and it's impossible

I just did a similar slot in steel with HSSCo at 1400rpm@40mm/min. One rough pass 160 mm at 4 minutes no coolant.

I know this a bit of an older video, so OK great use this type of slotting operation to make a first operation slot for a t-slot. But any thoughts on advantages or disadvantages of using that type of tool path as a second operation with a t-slot cutter?

Awesome video! I've actually just started playing with this technique as well. Have you tried it any using an indexable endmill? Should be able to absolutely crank up the feed rate with that and lower tool cost for inserts over a standard endmill

Not trying to be critical just trying to help always climb cut you will have a better finish and you will have dramatically increased tool life and if cutting steel with this type of tool path run dry just keep air on it

Hey great video. Like many have said climb milling is the best but without having machine shop knowledge you are doing really good. Problem we have her in a Florida is that most machinist are old school and stick with the traditional slot milling tool paths will Cobalt slow roughers. When I show them HSM they flip out when they read my feed rates and often I see the machines running at 20 to 40 % because they don't know better. but as soon as they walk away I turn it up to 100% and when I show them that it works they are amazed... they still don't beleive in it but little by little I'm turning believers into non believers. Technology is turning this world around and Im glad your showing the world what technology can do. Now change that federate to 350 IPM and really be amazed.

I don't know if this has been mentioned yet regarding your second pass issue, but I believe if you changed setting from conventional to both this would be eliminated. The second pass back I believe is to keep the cut conventional but by enabling climbing as well it should cut full width in one pass. Hope this suggestion helps :) I've never used CNC or even a DRO for that matter, I have a Cincinnati no2 mill and a 20s vintage Rockford lathe

Awesome John. Glad to see you using trochoidal milling. Its fun once you get that feedrate cranked up plowing through material. That aluminum galling is from too much heat in chips from to slow feed rate or re cutting of chips that aren't evacuated. Good deal though man as always even with your level of knowledge. These guys that are crabbing about their old places of work n such saying your lucky just had stroke of bad luck at those places. Your doing good man keep it up and always remember that the best experience comes from experimentation.

Way to go. Don't be afraid of cranking up your feeds and speeds with a tool path like that at is doesn't load the spindle by very much. When I was making a spanner wrench out of 6061 for my lathe to remove the chuck, I used mastercam x7 with their 2d HSM tool path to be machined on a Hass Mini Mill. My initial speeds and feeds were 70 ipm at 4200 with at 1/2 2 flute HSS endmill at a 6% step-over and full depth of cut (.750). By the sound of the machine, I knew I could bump it way up. By the time I was finished tuning, I maxed out the spindle at 6K RPM and ran the feeds at 200 IPM. The spindle load didn't go above 25%. Absolutely no chatter and it only took 13 minutes with a finish pass to machine. I know that tormach is capable of more, don't be afraid to take advantage of what it has to offer. cnccookbook has some great info on HSM and stepover.

This is cool. I was doing it the old way. Great channel!

Surface finish, too late to go back and check now but tool runout, it's a lot more obvious at higher feed rates, I have also heard it said that for every 0.01mm runout you can expect roughly 3% less tool life, and with a closer look you can often see/measure more wear on one side of the cutter. Food for thought, I'm enjoying your videos! Keep up the good work.

Fantastic vid John, as always. I've never tried those endmills for aluminum. Well wait, I did try one but crashed it right away and never got around to trying another haha.

ok, lemme give you a few bits of wisdom that i did pick up in a machine shop: 1: anyone who tells you you need separate finishers for aluminum is just trying to get you to spend more money... any chinese non-coated 3-fluter will cut that shit like nothing. its carbide vs aluminum, thats like steel vs peanut butter... ive gotten

its vids like this that make me want to convert my mill to cnc. great vid

no climb cut?

Totally Agree with the lack of constraints. The school of hard knocks is an excellent instructor.

Hey first like your channel. Second is there a way in your CAM to up your step over to get it done in one pass? Otherwise just add stock to leave and do 2 contour passes thus would get a better surface finish and hopefully get rise if the "ripple" effect

hey man ive watched your channel for quite a while now and love it. fair play man you have came a long way to be honest. i just wanted to mention ive been in aerospace machining for 7 years now and recently we started to use cutters that were chatter free. in my opinion the best finishing tools ive ever used....just a thought for you incase you have not heard of them before.

Thanks for video. Did you find the error for the extra stock?

Hey NYC CNC, I really like your videos. I just recently discovered your channel. I work as a CNC programmer and have been in the business 11 years. It's fun to watch someone learning different techniques of machining and doing testing. After watching this video I had a question. Was there a reason you ran the roughing tool path conventional cut vs running it climb cut?

What version of Sprut are you using John? I tried to replicate the tool path issue you were seeing and my version just generated a single pass tool path. I then made the slot width wider and sprut generated a spiral path down the center and straight paths to cut the rest. I'm using version 9 build 0.2 Rev 75511 x64 RL.

Hey John, I've been enjoying hsm paths lately myself. I don't have that odd hsm return you're experiencing. In SPRUTCAM I use the third option 'pocket step' I think it is whereas you appear to be using the 'pocket step and clean up' (or something to that effect - the fourth option). Try the third option and let me know if that is what you're after. Regards, bk

Nice job. Thank you for sharing.

Good video! Hope there are more just like this. This is the type of info that is sometimes hard to come by unless you learn it by trial and error.

How about to use a saw (various thickness) to do a rough cut first?

The slow-mo shots are awesome.

Lots of comments about climb cutting vs. conventional. What actually is happening with a conventional cut is that you are cutting into the material as you feed toward it, so the cutter has to push the chip into the metal that is going to be removed (more heat and load on everything). With climb cutting you are hooking the material away from the mass and ejecting it in to the void you have just made (that's why the tool seems to pull into the cut - use caution on a manual machine by snugging up the table clamps).

Once I learned about HSM techniques, I have a hard time going back to the old way of machining. I find it helps small machines act like bigger ones. My little X3 mill does things I never thought possible with HSM techniques. I wonder what "herbie" could have done!

Cool stuff John, how much time do you think you save with he new technique? > 50%? Almost looks like it could be that much.

What accuracy and repeatability from Tormach. Watched some one else just trash Tormach 1100 and I wanted to ask you your opinion

Ive been using trochoidal milling for about 2 years, efficiency of our machineshop has dramactly improved when combined with quick change fixtures.

Peel milling is the way to go. Full flute cuts. I use this tool strategy every chance I get. HSM has a very nice option to do so. Your going to find out you'll save sooo much time. And let's face it, it looks pretty bad ass when running. Awesome video. I see more high speed machining in your future...... :) Phil

do you know if it is posible to do this type of circular cut in fusion 360?

Thanks John for the awesome video. I've never seen that method of cutting a slot before. When I was taking my machining course we did an experiment to see what methods we could come up with to make a slot faster. Trochoidal was not one of them unfortunately. However we tried the convention way (your old method) and plunge milling (centre cutting end mill used). Plunge won hands down including clean up cuts. However tool life I believe would certainly loose big time. Trochoidal would be a win win. One of the great things about having your own shop is the ability to test new ideas and experiment at will. When you work for others, the chances are you can't do that. If you find the solution to the second pass issue, will you post it please? I'd be interested for sure!

is there a point where the trochoidal milling makes so many extra moves that the ways or ballscrews wear out faster? I'd rather an endmill wear out over the linear bearings or whatever. Just curious if anyone has talked about this before?

hi thanks for your videos, could this be done with hsm??? i cant find the option...please help... thanks

Small mills and trochoidal tool path strategies are wonderful for increasing speed. As mentioned, climb mill, figure out how to maximize the circular path to one pass with a contouring clean up, and with a 1/4" 3-flute aluminum rougher at 5100rpm and a 25% step over in trochoidal, you should be easily able to run around 35-40ipm (on your Tormach) for that operation. Get your FLOOD running, and add a flood wash down handle (I use coil garden hose and an adjustable gun type hose nozzle). You will wonder how you managed without. I can spray my enclosure/mill down and all the chips end up in an easy to remove pile, then airblast any puddled coolant off the mill/enclosure, takes 5 minutes at the end of the day and the next morning its clean and chip free for the next set of jobs or fixtures. Really liked the slow motion, would love to see a similar slow motion of it climb milling at the more appropriate higher feed rate, you will notice a nice stream of chips in one direction which will let you know your dialed in Keep up the great work! Chris PS... I run an even smaller G0704 mill so if it works on my 350lb lightweight, be assured it will work even better on your Big (to me) Tormach.... Hahaha

Sir! How to cut dashed arc, circle and dashed (axis) line profile. Please make a video with a written cnc program. Thank you sir. I need to know how to write a program to cut such profile. I asked a sir at my college but he didn't know to write such program. Your help will be very useful. Thank you

How does the finish compare between the first tool alone, and the combination of the first and second tool? The Lakeshore Carbide tool is advertised as a finisher-rougher, but I wondered what your experience has been. Thank you.

What many people forget with trochodial milling, is that it puts a HUGE load on your machine when you have a moving table. Especially with me, we have a machine with anx axis of 1600mm travell, if i go trochodial, its gonna wear the machine down realy fast.

Do you use coolant on carbide? Or just air . I here not to use mist , after I used it .

Be interesting to see you revisit this with Fusion360 and what you know now...

Well done on figuring out modern methods to enhance your Machining capabilities. if you ever need any help or any Machining tips , feel free to give us a call. manufacturing knowledge should be shared.

wouldn't turning your cut percentage up get rid of the extra pass? and you are blowing oil though your air mister right?

Great video man. Cool to see that a totally different approach can have such drastic results. Smarter is def better.

if you have a rpm of 5100 you should be feeding at like 35ipm if you use that dynamic milling. and climb cutting will eliminate that chip weld.

Did you figure out how to make the full width of your rough in one pass? I was wondering if it was related to conv/climb/both. You said you were running "both" but on screen you just showed conventional. For something like that I typically run mixed or both.

Did you ever figure out the spacing issue in the cam? I don't have sprutcam, but with mastercam you can tell it how big the "Toroidal circle paths" are, I also think its called peel milling...

@13:17 It almost looks like you've got runout issues here, looking at the holder itself, which may be contributing to the less than optimal finish when the feed had been overridden. I wonder if you managed to get it going faster and better since?

Hey nyc cnc I always look for speed and feed slider charts from tooling companies my favorite go to slider right now is a niagara one. today I ran a 3/16 swift carb 4 flute at 8000 rpm in some 303 ss I forget the feed rate but it was pretty efficient and definitely hsm worthy speeds and feeds with no damage to tool. maybe check out niagara I've used it on lots of different end mills - works great and it's free.

Funny how one shows stuff mostly on aluminum ....which in most shops it's not the usual material. And..if your'e in high production, the fasted and best bang for your bucks for this job would be a side milling cutter, one cut only...also in steel.

great tips again mate. Ive been looking to try this for a while, and finally today gave it a shot on some aluminium plate. Results: A slot that used to take my little 6040 about 20min now took about 8 - and went from a .5mm doc and sounding nasty to a 3mm doc, with 1.5x the feed rate (1000mm/m), sounding like it could take 4mm+ - and thats with dry milling on a cheapo 6mm endmill.

I was noticing just how little oil is spat out of the MQL nozzle during one of the slow-mo clips. Pretty cool. ...unless I'm being fooled and that was air-only with just some residual oil in the tubing. And hey, big step up for my shop: I purchased a Bridgeport Boss 8 already retrofitted with Mach3 in absolutely amazing condition last weekend. Thanks for the vids as always, man. You're a huge help.

Hey John, just got a question about the Tormach Quick Change System - what's the diameter of the tool holder shank?

We had a job a lot like this, 0.25" 3FL carbide, 24000RPM, 0.5" depth of cut, trochoidal climb milling 375 inches per minute. Made a super quick "ZRZRZRZRZRZRZR" sound and we did an 8" slot fast enough you'd miss it if you yawned. Fanuc Robodrill can really make chips fly!

Have you looked at the trochoidal milling software on the Seco webpage ?

I slot at full depth up to 3xD. More than that one hen I trochodial or if my roughing took is too small then I use trochodial cuts at full depth and at least 45-70% engament

As others have said, climb milling the high speed toolpath will yield better results. You can leave less material without risking gouging the part. Also, think of the feed in terms of chip load. We typically run 1/4" tools at 150% axial depth (3/8" depth) and 25% at 150+ IPM at 12k rpm. Depending on your spindle power the tools you are using could feed at 60+ IPM without risking breakage. Try it out, you will be surprised and you will really see the benefits of high speed machining. The tools will take a lot more than you think and if you are machining parts for $$$ you will come out way ahead by pushing the tools, wearing them out, and replacing them rather than trying to make them last. For similar slots that are 2-3X deep my preferred roughing a slot like that is plunge roughing with a 25% step over.

Is there a reason why you're conventional milling? is there a plus to this rather then climb?

where is a good place to get aluminum and what does it cost?

Running a 3rd axis milling machine with a 16 tool carousel, with a production spindle speed of 8,000rpm, I run 1/4 inch carbide end mills going 25-35 ipm, taking 50 thousands at time with a 5 thou, wall clean up. With a run time of 2 minutes.

Hey John, Whatever happened to your Atlas horizontal mill? Seems like that would be the perfect solution to your slotting problem ;-)

if you do a lot of slotting horizontal milling is the way to go, I've seen a lot of your videos and I'm sure the shop has room for a cheap old bridgeport dedicated for horizontal milling. just a thought.

Thanks for the great content. You make this look deceptively easy. I worked in job shops for a few years and know it’s not, even though it should be, but that’s another subject for another time. I like the slotting technique. In keeping the “out of the box” thinking I thought I’d share another nifty trick, this one for the manual lathe, that I thought you might find it interesting. I found it on You-Tube and regrettably, I can’t locate it again to give credit. There are times when one needs to be able to control the cross slide to fractions of a thousandth of an inch. The resolution however typically only goes to .001. The solution is to turn the compound (the thing the tool post bolts to) to 7.5 deg. With that done, the compound dial will move in the Y axis in a 1/10 ratio with the Z, i.e. for every .001in you turn the dial you will get .0001in on the Y axis (don’t forget that Z movement if you have critical Z features)

Have you considered using 4 fluted solId carbide end mill for finishing? In aluminium you should be able to double your feed rate. They are reasonably cheap and last for ever. You could even use one tool for cutting & finishing, saving yourself even more time. Have a look at Sumitomo Electric carbide tooling or Sandvik Coromant, they are fantastic tools.

I am learning like you and sometimes when you work in places with old tools and machines you are learning tricks you can use in future for fast machining. Well adaptive clearing is good thing, but I think you do not need software to machine that slot. You can program one pass and use it as a local subprogram and just repeat it. You just calculate the number of repeats and after that you will do that finish paths and you are done at least that how I see it and the full program for that will be done if just few minutes.

Experimentation like this is great fun. I have spent quite a bit of time doing this even with manual machining as well as other engineering projects. Btw, if the tooling from McMaster is not marked, call or email them and ask who makes it, they will most likely tell you. They can also special order just about any brand name you are looking for in anything, this is good for companies who have limited purchasing options outside of certain vendors even though they will often pay more.

There is a disadvantage to this. I like the small Ap's and large feeds because I can just sharpen the endmill's end, instead of grinding the flutes, wich is a pain. It is a bit slower for a production enviroment, but for single pieces like I do, the programming time is much longer then the machine time anyways.

can you suggest lenses for the same.

I know this video is4 years old now and youve probably learned allot, but a couple things I noticed. first you were wondering how to eliminate the last pass on the side. the easy fix is a looped sub program. look at one level of the code and make that a sub. then loop that sub. I'm an Iscar Rep from New England and I see this kind of thing all the time. create the path using incremental and after the circular interpolation, create your incremental X move to position the next arch. make that a sub. get to your start point and start the sub using a loop. loop it how ever many times it takes to get across the part. this is not only way faster but the entire op only takes a few lines of code compared to probably thousands or at very least hundreds. lastly, climb mill and determine your radial chip thinning or thickening. use that to determine your actual feed per tooth and apply that to the recommended sfm. in this case you would have chip thickening so if your normal feed and speed for a 4 flute 1/4 inch end mill was 1200 sfm and .004 per tooth, your normal feed would be 293 ipm. but due to chip thickening, a .0011 fpt would give you a chip thickness of .004 so your adjusted feed would be 84 ipm. all this doesn't even take into consideration with HSM, Dmilling, Tricordial milling your able to elevate your sfm 2-3 times the norm as the tool is always coming out of the cut and cooling down. unfortunately most folks don't have 40k spindles to take advantage of those abilities.

With my giant manual boring mill I shove it all the way through than go one step to each side. Do it even faster than that. But I have a lot more rigidity as well

I thought it was a good video. I'm just a machine operator and don't know allot of things besides how to operate and setup a bunch of different brands of machines and styles (fanuc/convo/horizontal/vertical/3&4 axis/ multi-pallet cells) . But I always find your videos educational even when it's something I've done before because another perspective is nice and you explain things for the laypeople. I didn't go to school or really have training, I was kinda just thrown into machining when that department needed people and it's been a trial by fire since. Hopefully I can have a small work shop like you someday with just a couple manual machines and try to make my own stuff.

John, do you know if that particular machining strategy for slots is exclusive to SprutCAM? I can't seem to find a way to get HSMExpress to do it. (I've been slotting the "wrong" way myself with multiple DOCs.)

Does "HSM" actually mean anything? When I select "HSM" in GWizard for aluminum with a 1/4" carbide + ZRN it recommends spindle speeds of 20,000 - 38,000 rpm and feeds between 40ipm and 400ipm+ depending on the depth of cut. The cut in this vid looks more like old-school low speed / low rpm milling. So, if HSM does not mean using either a high speed spindle and / or a high speed feed rate... then WTF is it?

I'd love to sit down for a beer with this guy. he seems very book smart and knows what he's talking about but I'd love to show him a few tips and tricks. Really get those tormachs humming.

how would you program this using G code? G42 with a G01 somehow?

I usually enjoy your videos, but I'd like to make my own observation on this one. Lets analyze your tool path. One.... the approach pass, 50% of your tool motion is wasted movement. You're not producing chips. Two...On the return trip, at least 80% of your tool motion is not producing chips. This would also be much better as a climb cut since this small diameter cutter may dig in and exceed the channel boundary under load. A single pass would be a huge step in the right direction too. Possibly you have a corner radius defined on this tool in your tool definition, and thats why the second pass showed up. All totaled, I bet your table actually moved farther using all those circular movements than if you would have just run up and back a few times. I like your channel, skill and material, but I would never use this technique.

Good video! But why are you doing conventional milling instead of climb milling for this?

I am not getting something, to make that cut why not just run a 1/4" slit saw (horizontal end mill) on an arbor?