Practical approach to milling sheet metal
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- Опубликовано: 7 фев 2025
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You taught me a new technique! The few stainless sheet jobs I have done were a nightmare like your dramatized beginning.
Never to old to learn something new and thanks for your great content.
ATB, Robin
Thanks robin! Good to hear the learning never stops :-)
Oy, glad to see you around Robin... Been a while since you posted anything, i guess you are flooded with work, so i am not going to bitch... It`s not like i don`t rewatch your videos every so often, just as i do with Stefan`s work...
Hope you are doing well!
All the best and kind regards!
Steuss
Stefan you’re a brilliant teacher. I finished my apprenticeship a decade ago and still learn something new every time you post a video.
Thank you!
At 12:45, my hand was throwing away my cup of coffee and reaching for the E-Stop.... I broke more than one endmill milling flat sheets like this, held down by clamps not modeled in CAD. Personally, i love those kant-twist clamps. Problem is, my endmills hate running into them at G0🤣Also, at 15:50, i would highly recommend using two clamps. Otherwise, the cut off piece tends to rotate below the clamp, getting pulled into the cutter.
Another masterclass from Stefan, but the "neglectable" at the end puts a smile on my face
Yes, I'm going to use that from now on. Sounds better.
@@ColchesterBridgeport Yes I used to work with a Russian guy who regularly made inventive use of words that when you look at them closely, were not incorrect. I think here "negligible" would describe the burr, "neglectable" describes his attitude to it.
Excellent video Stefan, as always. Thanks for sharing your knowledge and expertise with us.
Thank you!
I wish you would have shown this technique a week ago would have saved me a lot of heart ache. Never mind I’ll start again and put your info to good use. Many thanks.
Great advise on using chamfered corner endmills. I recall you mentioning those before and I really need to order some. In addition to clamping the waste stock, using tabs helps keep off cuts from getting thrown around and jamming. I do a lot of milling of ~1mm (.040) aluminum sheet on a small router. Using the tool probing and material mapping helps with the initial cut on GRBL based CNC routers. It helps to use a sharp pointer to do the mapping with a slow Z feed to avoid deflection on thin sheets. The control then compensates for the height variations and it really cuts down on burrs. I have not seen this feature in real CNC machines, but i assume anyone running those has a better processor for cutting sheet metal.
Excellent video, answers a lot of problems I've had with sheet metal milling looking like someone chewed it off ! You know I'm going to learn somethng when Stefan gets the pen and paper out ! Thankyou !
Depending on the size of my raw material and the size of the finished part, I will use a spray mount adhesive to mount the metal to the wood. The adhesive is gives an extremely strong bond so you can clamp the material much farther away from the cut path which means it's less likely to bow. Also, I will sometimes use Medium Density Fiberboard (MDF, AKA Medite) as it is usually far flatter than your average piece of plywood. If you use coolant it will pretty much destroy the MDF but that's a small loss. To remove your part from the MDF, apply a bit of heat from a heat gun and the glue will soften and release the part.
Absolute wonderful video! I have never given this process any thought and would have done this machining operation in one pass. Thankyou for sending me on the right path1
About 3 weeks ago I had to make about 24 small impellers at work out of 16 gauge 304 (should've been laser cut but we don't have a laser cutter...); I ended up going full DOC and using a roughing end mill and lots of coolant, lowish feed rate (I want to say 3.5 IPM on XY?) They turned out OK. That being said, I'd really like to try this technique as we do a lot of sheet metal work and I have a nice new ProtoTrak bed mill to use. Thanks, love the channel.
Thank you Stefan for the masterclass. Interesting and informative from beginning to end. 👏👏👍😀
It's very rare that I cnc sheet, but sometimes I have to do 1.7mm cold-rolled. I picked up a couple of cutters the same as I use on my wood router at home - downcut spirals that tend to push the work down. (The sheet has a wood backer the same as you showed).
I have yet to try downcut spiral cutters - Do they well?
@@StefanGotteswinter They're very good. I use the same method as you - fairly shallow cuts and faster travel - but still suffered with chatter and vibration with 'normal' mills, especially on the breakthrough pass. The sheet wants to catch, grab and pull up at any opportunity - there's just not a lot of rigidity to it. Downcuts help a lot.
Very well explained,Stefan.Thank you.
Thanks Stefan. That was very interesting. I was an expecting an April Fools joke but I'm glad I watched. All the best, Mart in England.
Indeed, that works way better. It's all in the details.
This is something I think I would never have figured out myself.
Thank you Stefan, for this lesson. As you explained it, it became obvious that your approach is how it should be done.
Always learn something new watching your videos. Thanks.
Danke für den Tipp und die ausführliche Erklärung! 👍
That is one to remember for sure . Even for large cuts on my other mill ( 4 1/4 ton Stanko ) with a face mill i often go the multiple lighter cuts, high reed & rpm . Seems quicker & less load on the machine . 👍
Very useful. I just milled some stainless sheet and the end mill (about 6 mm dia) was fine for the first 20mm. Then it got red hot and end of cutting. I was cutting full sheet metail thickness. Then I swapped to another cutter and used very small DOC as Stefan describes. OK job. Great to see Stefan is describing exactly what worked for me. Thank you Stfan - pity I didn't see you video before I started my job!
Bummer you burned up the cutter, but great that it worked out well in the end :-)
Stefan, this is a great video. I have liked milling cutters with a chamfer for a long time. I even "save" the ones that get their corners worn by hand-stoning a chamfer on them. But I have never thought that a chamfered end mill would be good for thin/sheet metal.
Along with taking shallow cuts and using a high feed rate, I have really learned something today.
Thanks for a great video!
I will be trying this approach on cuts that need it. This, id scribe, band saw, one rough and one finish pass at full depth.
Sawing and finishing is always a great alternative, if the contour allows it.
@@StefanGotteswinter Not trying to be a dick, but then show that contour. Maybe it's just me, but I find it unappealing when the test piece makes no logical sense to the demonstrated tool path.
@@greggraham247Well, have some phantasy. Unfortunately the parts that i in the recent time did where all no-show/NDA.
anything thats a small later-to-be-stamped part. anything that requires larger numbers, where babdsawing is not efficient. Anything that needs more than outside contours.
Open up a moder GFI switch or a modern breaker switch - any of the sheet parts in there.
Very informative and helpful video. Thanks for posting, I know it's a lot of work to make these videos so please know it is appreciated!
Well done in all aspects. I have a few projects using thin metals I've been putting off for lack of knowledge/expetience. I feel much more confident I can take them on, now.
Close to 10 yrs ago, I was in the market for my 1st lathe or mill. Looking for a machine, I saw an ad for end mills, '40 pounds of end mills, $35.00'.
Knowing nothing about end mills other than they aren't cheap, I went to look at them. 95% were brand new, some still in the rubberized protective coating.
Got them home & was looking at one, to chk the cost on the 'net.
My heart sunk when I saw the corner of the flute chipped off. Being ignorant of something, the 1st thought is, 'No wonder they were cheap. They're effed up.'
Started looking at each end mill. At the 3rd-4th, I realized they were all 'chipped'. By then, I began to get familiar w/ them & realized the 'chips' were very uniform. It was then I understood they weren't ruined & it was a great deal, after all.
I got a lathe that same day, but it wasn't until last year before I got a mill, (cancer detoured me for 4+ yrs) & I've been able to put the 40# to some use.
I've read a lot & watched a lot of vids about end mills & milling in the intervening years. You are the 1st to discuss anything about chamfered flute ends, their use or even their existance.
Thanks.
GeoD
Stefan, I've been dealing with this very issue today trying to get a good clean cut on a customer's part. God bless you! I changed my approach as you suggested, and i am now going to be able to deliver descent parts. Cutting .8mm 316L Stainless Sheet using 1/16 inch diameter end mill. Now my cut matches the mirror finish on the material! Beautiful!
Another great video Stefan. The chamfer on the end mill at high feed is forcing the material down into the spoil board. I wonder if the edge finish improves with a aluminium spoil board so there is less micro material movement.
Maybe the spindle bearings are loaded up just a little more with the chamfer cutter also. All these small things that make a difference are long in the learning, but with the help of your excellent videos, im sure most of your viewers are getting bettrr results more often. Thanks again.
We do quite some stainless sheetmetal (13-8PH) and to be honest never had issues with just going full slot and as fast as possible. Key is the fixturing imho. I only use precision milled aluminium plates as a backer and drill a bunch of holes to really clamp down the sheet. Think this also helps with getting the heat out of the sheet and into the aluminium. All roughing is done with a 6 mm 3-flute from Garant and finishing with a 4mm 6-flute. And a VMC with TSC to get the chips out of the slot also helps..😅
This is a lucky coincidence. I have to do this exact thing Monday morning. Same material and all.
Using the painters tape / super glue hold down works great but be careful with really thin stock because you’ll destroy the material prying it apart. I soak it in acetone
Another aspect: For slotting (on home shop/less rigid machines) the 3 flute endmills work better than 4 flute ones. Which kinda makes sense with lower cutting and pulling forces (from flute helix). The surprising bit is that 3 flutes also work better than 2 flutes. With 3 flutes the load (both magnitude and direction) on the cutter varies less whereas with 2 flutes when one flute starts disengaging the other starts engaging. This results in the cutter forces making an almost 180 deg switch, producing bad vibrations. Worse, because the shock loads happen when the flutes are engaging the sides of the slot, overall the slot will end up oversized. Actually, the same shock loading will happen when slotting with endmills with any even-number of flutes though the shock will be less for 4+ flutes and expensive variable flute geometry cutters. But don't just take my word, make similar slots with 2, 3 then 4 flute endmills at the same chip load (or less scientifically same feed) and listen for vibrations and measure the slot width. Do check the runout (on the flutes) of each cutter beforehand as that can easily be bad enough (from bad collet, spindle, debris or wear) to invalidate the test.
Actually this is very helpful to me, as I've just had a nightmare in the workshop trying to mill stainless sheet, so this video is timely, albeit a bit late for me, I could have done with seeing this before I ruined my cutters! but now I'm a bit wiser, so thanks for this.cheers, Dave
as always Mr. Stefan you educate us with another informative video ! thank you for all you do and taking the time to show us.
The one thing I learned about drilling/milling/turning stainless is to use water. Basically flooding it with water keeps the temperature low and prevents stainless from hardening. At work we use cheap hole saws in stainless and they last a long time as long as you cool them with water
Thx for sharing this tip, very useful. I also (sometimes) hava to fiddle around with sheet metal, and in stainless you have to watch out for workhardening. Gruß aus dem Badischen, from another Stefan :)
Thanks Stefan you're brilliant. This will help me a lot. I'm planning to make kant twist clamps. And that's a lot of cutting in sheet metal.
I made a set years ago out of stainless. They were a pain to bandsaw out due to work hardening. I used them a lot but they were actually too big for the plate l used for the sides.
Hello Stefan! I have been watching your channel for a long time and thanks to you I receive a lot of useful information. Thank you so much for sharing information with us. Big greetings from Belarus, Minsk!
Stefan thanks for another very helpful in depth tip/trick. Always enjoy your tips and musings, First Rate Stuff!
Thanks for sharing. Today was the first time I successfully used a self-made 1-tooth cutter to cut a 'Simmerring'-seat 4 mm deeper into cast iron. Having watched over your shoulder over all those years was all it took. Thanks.
Really enjoy your vids Stefan. I’ve been a hobby machinist for 20 years (stress on ‘hobby’) and i always enjoy how you break down details so i can not only learn how but why. Thank you
Very helpful. Air starting/wood thickness variance and end mill discussion are my takeways. Thanks from Colorado.
Thanks for sharing your knowledge and experience. I'm a little wiser today 👍 🇬🇧
Another excellent tutorial Stefan. Hope all is good in the land of precision machining and Black Forest cuckoo clocks. Cheers!
Exactly what I needed, as tomorrow i need to millout holes in some electrical panels. Earlier tried full depth and that was not nice. Will try this approach. Thanks for the video 🍺🍺🍺
Thank you Stefan. I run a CNC Router on Aluminum and Hard plastics. This information will serve me well
Very useful. Thanks Stefan for sharing this knowledge and happy new year!
I use that technique in wood or plastic or metal cutting.... it takes a little longer but usually it is almost as fast..taking deep cuts heats up your blades / tool and is harder on your Power tool too... shallow multiple cuts are going to be easier on your tools ..reducing the heat and force needed to make the cut depth.. . it is something i learned about 40 years ago and i find it the best way to do cuts.... i don't care if it " seems " to take longer because i know it is going to allow me to do the cuts without problems every time....especially when using Piwer tools that are just powerful enough but doing long cuts it is going to overwork your tool and the cutting tools too... you can relax and get alot done if you are patient....
🇨🇦🤓🤟
Thanks Stefan!
You never disappoint!
You're always on your game!
It's such a treat to be able to freely benefit from your knowledge and experience!
I'm so glad you choose to share all of this great info with the rest of us!❤ 😊
Massively helpful! Sehr hilfreich. I wish I'd known this, two years ago, when I tried to make myself an instrument panel by milling sheet steel clamped to plywood. It was a total dog's breakfast. (Früstück des Hundes?) I concluded that a Bridgeport was not a sensible machine to use on thin sheets... but you have shown me that it can be done, if one knows how. Thank you.
Many thanks once again. Very concise presentation, valuable information.
As always, excellent description and discussion, understandable and convincing. Thanks for continuing to share your experience and expertise!
Brilliant as always and many thanks for this machining tip. I have a somewhat tricky project coming up where I have to cut square windows out of a curved piece of aluminum. I better come up with a way to clamp the center part so it doesn't jam or ruin the cutter. Obviously clamps won't work as the cutter will pass through its position. But, at least this vid has made me think about it.
Thank You Stefan for this very useful advice!
I have used MDF board similarly, find it much flatter than plywood.
Usually glue a piece of hardwood to the back for quickly putting it in the
vice for less critical stuff. Easy to attach clamps around the sides.
This is a great tip. Thanks! My last low precision sheet metal project I glued a 1:1 scale drawing to it and cut it on the bandsaw
Thanks for the tips and demo Stefan, always fun to learn a little something looking over your shoulder. Thanks!
Great video and very informative. I’ve been using the super glue and painters tape hold down method like NY CNC on an aluminum plate for thin stuff and it works great. Actually, not just thin stuff. It works great at anything I want to get around without worrying about the clamps. If I don’t hold it in the vise, I’m probably gluing it to a plate. I even glue pieces of aluminum scrap to the top of the vise hard jaws to make soft jaws out of for smallish parts. You’d be surprised how much force it takes to break them loose. For really thin material, you need to use heat or solvent to break the bond because prying them apart will actually bend the part
I used that method too several times, but usualy ditch the tape and superglue the material directly to an aluminium plate - Its a bit more annoying to get rid off again, but the higher rigidity is worth it for me (Also thickness tolerances can be hold tighter if necessary)
Ich nutze meistens meine Vakuumspannplatte für Blech. Dadurch ist es von der Höhe her sehr gleichmäßig.
Ab und zu nutze ich auch die Technik wie du sie hier zeigst. Das Abfallstück sichere ich mithilfe von 2-3 schnellen Bohrungen mit dem Akkuschrauber und ein paar kleinen Spaxschrauben. Dadurch hat man auch keine Störkontur durch eine Klemme.
great tips, great explanation (as always). also some of these tips apply to different areas of crafts too, eg don't clamp bendy wood in multiple places when cutting or resawing. Fortunately I learned that using cheapish wood and not metal :D
Great tips Stefan. I have had some very ugly results trying to make cuts in sheet metal, both aluminium and stainless so thank you very much for sharing your expertise.
Excellent and really useful tips. Thanks!
Thanks for the excellent tip! That's one kind of cut I've done from time to time and it's nice to learn a better way.
Thanks again Stefan for the efforts You spend sharing this information.
Best Wishes to everyone.
Thanks Stefan, I think I have learned a lot here. 👍
Good to hear, thanks for watching :-)
Great technique! I’m curious about your thoughts on left-hand helix endmills for sheet metal? Robin has demonstrated this- they apparently push down on the work, eliminating vibration and also reducing burrs. I haven’t tried it, but it seems promising.
Thanks! Nope, I have no experience with them, but I heard that they are very helpful in low rigidity situations. But I wonder how they compare in a low-depth-of-cut approach, since the spiral flute is almost not engaged at all.
I learn something new pretty much every video You make, nice trick!
Exceptional video Stefan. Thank you so much for going the extra effort to show us why.
I love those Uvex safety glasses, look way better than the usual, gonna get some of those.
Stefan, you can cut even thinner material this way by sandwiching it between two sacrificial pieces. Also a shaped clamping piece helps enormously
I have not tried that yet - I usually superglue thin sheets down onto a surfaced aluminium plate. Thats how I cut for example 0,2mm thick gold.
Correction! I have done that for stacks of shim stock, with a shaped clamping piece (more precise: two - one for clamping the perimeter while milling all internal holes, than a second clamping piece to clamp from the inside, to cut the outer contour of the stackup)
I have found that using a straight flute solid carbide end mill for sheet metal is the best. The straight flute does not create the lifting forces that a helical flute end mill creates. The cut is more rigid with a better finish.
LBFU School, has always been a solid teaching tool...💯
My endmills usually develop an edge chamfer after I try to use them.
Thank you. Another wonderful and important tutorial 👍🏽
Great info Stefan . saved in the grey matter for reference . Cheers Ade.
I only have a small horizontal Atlas Milling machine. If you ever get the time, I hope to see a video for doing this on a similar machine. I have so much to learn, and work-holding is my biggest weakness. Thanks for sharing.
Thanks for sharing, Stefan! I'm going to update my OS to use this technique for sheet metal in the future. Thanks again, and I hope the world is the even better than the best it can be on your end. ^___^
great video Stefan, Another one to go in my apprentice training playlist.
Excellent as usual. Glad to see that you do not use some form of super plywood that will make go into depression. :) Very useful technique.,
Awesome demonstration and explanation, as always.
Thank you!
Thank you, Stefan; i‘m looking forward for the next hard-to-mill-topic 💪
I learn a boat load here. Stephan, you’re the best!
Great demo and really good advise. Thanks Stefan!
I guess this is the closest thing to an April Fool's joke that we're gonna get on this channel.
He did a great one in the past…..
oh Stefan has had some good ones up his sleave in the past... trust me... he knows what he is doing
I use double stick tape and leave two tabs to keep things from flying on the cnc.
You can try band sawing the corner out staying about 1/16 away from finish, then put it in the miller and side cut to finish, you will minimize your burr.
The other way we did was to take small cuts on the depth, staying away from finish then finishing it off. Please use oil otherwise you will kill the cutter..
Sure, but if you have a CNC, and if you need to do multiple parts in the same sheet, it really doesn't make sense to any more manual work than absolutely needed. Let the robot do the work for you :)
Even more so with materials like stainless that isn't fun to bandsaw..
Wow, thank you! Have resorted to my contouring saw and drill. Can overcome the 304 with high speed drills sometimes but sometimes I saw the drill come out of the sheet metal with a reduced drill diameter. Yikes. Tricky for me like an amateur.
Thanks Stefan! Great tips. Given the minimum chamfer available from your supplier seems to be 1 mm, do you think it would be worthwhile using a tool & cutter grinder to add a custom chamfer on occasion? I'm thinking if someone had quite a few cutouts to make, a smaller chamfer, perhaps also at a higher angle, might allow you to reduce the number of finish passes required, and perhaps a higher angle could increase the downwards force on the work and reduce the tendency for it to be pulled up by the cutter.
Edit: perhaps I should have said "lower angle"? I mean one with less Z and more Y.
Fantastic info as always.
Thanks for the sheet metal tip, I didn't know that!
Sharp edges cut great but are a fragile thing. Radiused or chamfered endmills are much more durable in my experience.
Thanks for that information. Thanks for the video keep on keeping on.
I don't know what it might be called in Germany or anywhere in Europe. But in North America, MDF due to how it's manufactured is far flatter than most plywoods for a backing board. It's also a lot cheaper. But it won't tolerate coolant or even cutting oils for very long. The wood fibers begin absorbing the coolant or oil, they start to expand which starts to break up the resin bonding and the piece literally begins to warp and fall apart. It also doesn't hold wood screws as well as plywood for part holding, through bolts with washers and nuts might be better in higher loading situations.
Yeah, MDF is a great spoilboard alternative! (Its called the same here, funny enough it translates to german with the same abbreviation: MDF = Mittel Dichte Faserplatte)
I've always had good results using adhesive and sticking it to your backing board.
Yeah it works well - But I am always annoyed by the sticky residue that gets pulled up by the cutter and smeared across the side walls of the material cut.
Thanks. I will give it a try
Thanks for sharing this approach.
As always, interesting. Two questions.
At first, I thought that helix angle was reason why full depth cut, giving more axial force, was reason for vertical vibrations. Then you compared two endmills which had different helix angle. Confirmed my thought. Then came the mill tip discussion explaining advantage of best tip geometry. Is helix angle important?
Second thought. 50 years ago, I learned about then quite new research by Sandvik about boring bar chatter. They found that increased feed sometimes gives no chatter. Is this still correct and general knowledge now?
Good practical information Stefan,thanks.
i saw a video recently about reverse flute end mills and thought they would work nicely in this scenario with light cuts and downward spirals to eliminate the burring. something to look at.
I was always curious about them, never tried them. Thats something I will eventually look into.
I have screwed internal cutouts (countersunk!) to the spoil board to prevent disaster. Often I use superglue, but if you get your part hot enough, the glue will bid you adieu.
From my experience, Your method is good and the chip thinning fast feed is sound . Most machinists only deal occasionally with stainless so getting a good understanding of it is difficult. I had the good or bad luck to work where we did ONLY stainless for 10 years. Thats when you find out eventually that most of the charts and book recommendations are bogus. The actual successful sfm is ~1/3 the recommended sfm. From my experience for your 4mm carbide setup it would be ~ 2100rpm vs the book recommendation of ~ 6500. You don't really want to see blue chips, no darker than honey with coolant. For HSS endmill it would be ~730rpm vs book recommendation of ~ 2000. For HSS you don't want to see any color on the chips. Keeping sfm down will keep your tools alive in stainless. Then you can creep up on it to find your max.
Strange story. I had a #7 drill bit that for years , drilled thousands of holes in 304 and never got dull. and a DO-ALL 1/4-20 tap that tapped thousands of holes without getting dull or breaking. I have never been able to find either in any catalog !😡 I STILL have them 20 years later.
Very interesting. Thanks. I’m sure it going to be very useful.
great video.
wood is a decent insulator ... so it makes the heat problems worse.
how many splinters did you get making this video?