Reduce Burrs, Chips and Craters - Milling Cleaner Parts
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- Опубліковано 6 вер 2024
- This video demonstrates the value of correct cutter trajectory for better burr control and less bench time after you're done. I'll also show you tips for machining acrylic parts without chipping or cratering it.
- Наука та технологія
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The drastic difference in burrs created by controlling trajectories can be clearly seen at 34 sec and 55 sec in his video.
I am not sure which is more amazing your knowledge or your willingness to teach us. Thank you
Thanks. Glad to share it.
I do not miss the smell of milling acrylic. Thanks for the tips.
It took Joe years to learn how to screw up parts on demand like that. I did it right out of the box! Amazing how much material was removed on the “finishing” or second pass around those aluminum towers. I wouldn’t have guessed the tool flexed that much first time through. Thanks for the well thought out demo, Joe.
I love the videos where something totally obvious is presented that you had never considered. Fantastic.
Hi Joe. Great video. As a finemechanical engineer and tool/die maker I know all to well about the problems with cutting plastics. Actually, I hate plastic and try to avoid the use of it where ever I can. Even with my 25+ years of experience on the job, I can still learn a lot from other machinists. Keep up the good work.
Great info for us that are just now starting out late in life learning to properly set up and use the correct cut tools.
When you make a lot of parts, reducing burrs is very important. Its good to know these things.
Had an acrylic project for some time, but wanted to wait until I learned how to do it chip free. THANKS JOE!
Thank you Joe for this excellent demonstration. I think your experience shown here is now burnt into my head forever..no burrs & breakouts ;-)
Great illustration of the principles involved. Thanks for making me a smarter home machinists.
Joe, a tip for when it comes time for you to machine the wooden sides for you canon project and you want to mill the part with the end of an end mill as per your Perspex demonstration. Place some scrap timber either side of the part you wish to make, in that way you will get a perfect edge on the part in whichever cut you make, climb or conventional, any breakout will be in the scrap part. Of course you must come in from either end first, to stop a breakout.
That is a good tip Dave. I will use that. I am trying to decide if I want a stepped side or rolling radius side. They both look good, but I am leaning towards the step side.
Joe, you will definitely need the sacrificial side wood if you intend to do the stepped side version. You will get a super crisp edge to the part with no chips / burrs. Have you thought what type of wood you will use, perhaps Oak or one of your American hard woods. Perhaps you should view a few wood channels to see what type of wood is out there and to see the sorts of finishes that can be obtained. Looking forward to seeing you make it, the barrel looked fantastic in your last video.
I learn something every time and I appreciate the last part. Aim small, miss small.
I watch tens of machining channels but Yours is deffinetly the best 👍Thank you Joe
Agreed. THe difference here is that Joe P. is trying to educate his viewers while lately many of the others are more content to shill for tooling companies to get you to buy their products.
Also Joe only puts up a video when he has something to say, unlike some who put up one or two videos a week whether they have something to say or not!
Thank you very much. I respect a lot of other creators and take this as a great compliment.
@@joepie221 so do I. Other creators also make great educational content and I don't want to belittle anybody.
thx for the video, great job! BTW, for milling plexiglas (but not for making videos) helps a lot to flood the mill bit with coolant (preferably water), lots of it. This totally prevents the chips from melting and will yield unbelievably smooth milled surfaces..
Greets, Bernhard
While many of your points hit home that one that most impressed me was the amount that was picked up on the second pass due to tool flex WOW. As always very educational Thank you Shalom
The deeper the cut, and greater the tool load, the more deflection you can expect. I did a video on that topic. you should go check it out.
Excellent demonstration Joe.
Thanks for letting us join in!
thanks for watching.
Man , I just love to watch your videos.Would have loved for my high school teacher to have that much interest and love for machining metal.
The same goes for me! If my college teachers taught me half of this knowledge...!!
@@arpadbrecska8178 Thanks guys.
👍 thanks for another post Joe. I instruct my students to always circular interpolate corners unless the job calls for sharp. Let the CNC do the deburing. Even in conversational programming. Use a .01" Conrad or more if possible.
You show things that I may never do. But I still learn something. Enjoy your videos..
... I bought a very well used Web 2S? Mill years ago. Never touched a mill or lathe before in my life. (65 now). Have mostly self taught myself. I manage to do what I need to do. (Short Southbend 13" lathe too). Hope to keep watching your videos...
Thanks. Good luck.
Hi Joe.
You asked the start of this video for an input from sheet metal people regarding the shear distance of a piece.
We generally try to have 1/3 shear and 2/3 break. This gives less wear on to top steel/punch as the shear is square to the top surface of the workpiece and the break is clear of the steel/punch.
Hope this helps.
thank you. I knew the fractions, just wasn't sure of the application.
Hi. 40 years in toolmaking press tools. I agree, 1/3 shear 2/3 break away.
Great shop knowledge! Thanks for making my parts much smoother Joe! 👍
As always, that was incredibly insightful and useful. Thanks again Joe.
Perfect timing as always Joe. A friend of mine just asked me to mill him some acrylic. I've not had problems previously but I suspect that may have been more luck than judgement! Will definitely be making sure I run some test cuts before getting to final dimensions!
If you have 8 hours in a part, its guaranteed to go bad in the last 10 minutes.
@@joepie221 Ain't that the truth!!!
I find the 'Pucker Factor' steadily rises , peaking prior to the inspection of the final finish pass!
One of the most educational machining videos on youtube! Keep it coming! 😀👍
Thank you.
Joe, thanks for taking your time to help all of us out....👍😎
Thanks Again Joe, I've got a job coming up that I'm glad I watched this to learn a new trick.
Hey Joe thanks for the lesson, Excellent video well done 👍👍👍👍👍
Excellent portrayal of effect of cutting direction. For reasons shown I prefer countersinks that have the single hole from the side to form the cutting edge. When sized correctly, the burr is turned back into the countersink and cut off, leaving absolutely no burr.
Check out my cutter deflection video. I think you'll enjoy it.
I normally will use a single flute end mill at first and then switch to a three flute end mill with a slight taper and I never get those breaks and dimples. Plus on acrylic I always use coolant so I prolong the life of the mill's cutting edge and keep the acrylic from melting. I do the same for aluminium most of the time and since we are both making two passes the time it takes for the cut is the same except I can take a lot of material off with the single flute at a higher rate of speed.
The trick I have seen is to keep the cutting edge as sharp as can be and a good coolant is a must for cooling and lubrication.
Wow!
Nothing like experience coupled with a creative mind!
I love your solutions to stuff.
I can see where a couple hundred parts with burrs on em would be a serious time and profit killer....
Burrs can be very expensive. If you have automated equipment to deal with them, fine, if not $$$$$$$$$. On my CNC, I always add extra code to cut the burrs off. Its time well spent.
@@joepie221 Great advice and no sense in throwing money away :)
Great video, as ever Joe, I always had great success with a single flute cutter and high rpm slow feeds in acrylic/perspex
Great information Joe. Thanks for sharing your wealth of knowledge with us mear mortals.
Glad to help.
I've had those problems - love the advice backed up by results in a demo (with predictions)... can't wait to try your ideas - thanks mightily from Sydney Australia
I've been having weird burrs rise up from some turbine stock I was thread milling... and now I know why... next time I'll climb mill them instead.. thanks for the info!
Former (and future?) IT guy here who now makes gears (and gear like objects) for a living.
Thanks for another great set of tips.
As a manual machine user I do still have some concerns about reducing burrs by using climb milling, as I don't want to fire the workpiece across the shop.
I guess the compromise is to conventional mill the bulk of the material and then do climb milling to reduce burrs once I am closer to final dimension, so as to reduce the forces involved.
"Climb" cutting is slightly more complicated the just which direction you have things running. When you go along an edge with half the cutter engaged the major cutting force is into the part being cut and not along its length, it's when there is only a small amount of the cutter on contact that the cutting force vectors cause the part to want to pull the work overcoming the leadscrew backlash and produce an OOPS moment.
Even with climb milling if the cutting forces are small compared to the force needed to move the mill table, or clamping force in the vice, you should be relatively safe, but you will still need to be wary of the possible outcome.
Once again another great video, as usual learned a thing or two, but mainly wanted to compliment you on the nice pictures- the spindle / cutter shots particularly seemed to evoke the lighting in classic machinery shots 👌
thanks. Its harder to do than many realize.
Jeeze, as a "green" machinist, or "butcher" would be a better word, I gave up trying to make stuff pretty. Sometimes my parts look good, sometimes they don't. Feed, speed, and different types of metal all kick my butt in the shop. I can proudly say that I get my parts to the right size but it takes me days to do so.
Joe Pie you make it look so easy, I have full respect for your skills! Thanks for this lesson.
Thank you.
A wealth of knowledge
Nice demo. enjoyed.
Thanks Joe for all the tips and demonstrations.
Glad to do it.
Two thumbs up on this one Joe. Thanks
A great example for this talk is common silverware. Most of it is made from sheet metal and you can see these features on a simple fork or spoon.
Thankyou for the excellent video, Joe. Can you please do a short follow up video on how you ground that chamfer tool?
Very different I enjoyed that very much thanks
Masterclass level. Thank you, Sir!
In aluminum you get just burrs. If you mill polyethylene you will get burrrrrrrrrrrrrrrrrs.
Try UHMWPE. Burrs are at another level of frustrating. Cut one, form 2 more.....
Great vid Joe. Thanks!
I have a trick for removing the small burrs off Aluminium. Let me preface it by saying that you need to carefully consider the requirements of the job's finish if using this trick and be aware that it is moderately hazardous.
I frequently de-burr Aluminum jobs by agitating them in a bath of 10~15% Sodium Hydroxide [Caustic Soda]. The reaction is quite vigorous and if you leave it too long all your other edges will become rounded and that may ruin the job - as will not agitating it, which causes blackening.
It is a handy trick for making all those burrs and rough edges disappear but note that:
1> Caustic soda is HAZARDOUS, gloves and goggles please. [If you get it on your skin it will feel slippery at first because it is turning the fat in your skin to soap, then it will burn.] Irrigate with lots of clean water!!
2> The reaction gives off Hydrogen which is explosive [only a small amount is produced in normal use] so it should be done in a well ventilated area.
3> The solution will get hot if used continuously.
A little, actually a lot, of common sense and machinists might find this a useful trick for de-burring or putting an even, matte finish all over small Aluminium parts that they wish to finish in a hurry.
Be careful with it guys and gals and don't forget the agitation or you will be starting again!
Keep up the great videos Joe.
I do this as well. Best method before priming and adhesive bonding of Al as well. The old sulfuric acid potassium dichromate bath was even better but nowadays non EPA compatible for sure.
@@erikisberg3886 Erik, never used acid/dichromate for this but it is a wizard laboratory glass cleaner. As you say, it is not exactly PC today because of the hexavalent chromium which is a genuine nasty! Cheers.
@@mousemade1 We used amoniumpersulfate/sulfuric acid as a substitute but it does not work as well as Cr for cleaning glass. (Also sold as no chromix or someting?) H2O2 muratic as for etching circuit boards works (also for preparing some stainless for bonding) but it fumes a lot and needs to be freshly mixed. The CrSulphuric mix gives Al a very special surface like short hairs that bond very well to adhesives and primers. Main danger of dichromates seems to be dust and spray inhalation causing rather unpleasant effects. And waste disposal of course. I often use an ultrasonic cleaner for small Al parts, the caustic does not need to be particularly strong or nasty.
@@erikisberg3886 Don't want to take up too much space in these comments but will say "Yea" to all your comments AND I always clean stainless with Hydrfluoric acid (after welding - never adhesive bonded it) and HF is a very serious nasty. A good burn with that and the cure is worse than the burn! Cheers.
i have a request: touch off techniques on the mill and lathe. we all know the paper strip trick and various other things, but i'd like to see what kinda tricks you can cook up for more niche situation like touching off form tools like radius cutters, or in strange places, etc.
The cannon ball end and small part videos show some.
@@joepie221 thanks
thank you
you need to wright a book the tips are great. be well amd be safe..................Bill
What you are talking about is much worse when the shear knives get worn.
Thanks
Great video. Very informative..
Thank you
Thanks for another great video.
So; to get the best accuracy on a conventional mill you cut conventional milling and deburr, to lose the burrs climb mill?
31:15 by hand, really, would never have guessed.
Humor..I like it.
That's right make your life (job) easy. Sometimes you can throw parts in a tumbler and rid or soften up the edges. It all depends.
Awesome!! I believe the “smear” phenomenon is plastic deformation if anyone is interested.
All of the process is a plastic deformation.
Hyss Im not an expert in solid state but I don think thats accurate. You sound very confident, can you explain?
Here is an interesting paper on the topic
a_viktor.tripod.com/plastic.pdf
There are 3 types of deformation,
1. Elastic where when stress is removed, the material returns to it's original shape.
2. Plastic where when stress is removed, the material returns to a different shape.
3. Brittle fracture where material quickly separates through the stressed area.
As your PDF discusses and, I believe is Hyss' and the video's main point, machining and other shearing actions that lead to burr formation should be dominated by plastic deformation, thus Hyss' statement "the whole process is plastic deformation." within the scope of this video.
Outside the scope of this video, elastic deformation does give rise to machined-in stresses and dimensional inaccuracy due to work-holding (reason surface grinders use magnetic chucks).
Finally, brittle fracture deformation can occur (as shown with acrylic cratering), but it is not desired in machining because it is unpredictable. Thus it too is outside the scope of the discussion of reasonable machining operations.
Tension Compression Shear I misunderstood that “the whole thing” was all of machining.
Magnetic chucks will also pull down thin material in plastic deformation, upsetting the operator!
Really cool lesson Joe, thanks for taking time to share. Might I suggest you try a head mounted 'action' camera for that kind of shot (perspex)? PS, would a ball nose cutter work as well as the chamfered tool?
Dear Joe will a right handed threading bar flipped upside down feeding in on the right side of part cut lefthand internal threads? Thank you love your vids . Maybe think about a video covering these combinations.
I think you could also avoid that crater if you lifted your cutter a tiny bit, made a small cut inwards, then went on the other side as you did, lowered the cutter once more and made the cut all across the length juat as you did. Then the tall part would not break off as it did here, and you would also finish the cut with a very small height of material in the end which would minimize the actuall crater to next to none.
A lighter final pass is a step in the right direction.
Excellent video. Now, I know how to make good acrylic control box front panels. Joe is there any reference material giving recommended speeds and feeds for acrylic?
Thanks for taking the time to make this technique know to us all.
Good stuff,thanks again Joe.
A picture paints a thousand words and you have created 25 a second for 35 minutes, keeping my attention throughout. Very good visual explanation as usual Joe, THANK YOU. I will think about this when I eventually convert my Mill. Just a thought, how would a Downcut Endmill cope with acrylic?
I know they are good for side milling thinner materials, but I have never used one to mill with.
@@joepie221 It may be worth a try as the forces are down into the material, that combined with climb milling may be another answer, just like using your self ground angle one. Happy milling Joe
The rattle in that machine would drive me crazy!. Sounds like 2 skeletons screwing on a tin roof!
Ah... the sound of the plastic bushings beat out in a Bridgeport variable speed head. The eternal question is: How long can you stand it till you break down and fix it....again?
The rear ones are much easier to get to than the front. Its the front ones making the noise.
Thanks for sharing!
Awesome video and demonstration. Thanks!!! :)
Very interesting, thanks.
Get a Onsrud or Amana single flute upcut for that acrylic. Night and day.
@Tony Wilson not sure? I make 420X vent slots/part with these: www.amanatool.com/51416-solid-carbide-cnc-spiral-o-single-flute-plastic-cutting-1-8-dia-x-1-4-x-1-4-shank-x-2-inch-long-up-cut-router-bit.html Onsrud makes great cutters as well. Works great on PC, acrylic and telflon. No chipping. Very little burrs. CNC paths... IIRC I did not find good results with delrin.
reverse helix end mills come in handy to minimize burrs, or even straight flute . . .
Excellent for holding down thin material too.
You can manipulate the burr with a die and punch. Depends on if you make a smal radius to the punch or to the die.
Hell yeah.... FREE STATE!!! As always, Joe, Awesome video. When cutting the original trough down the middle between the two towers, that would be both climbing and conventional? Teach me.....
Its both. Many refer to that as 'plowing'. A good rule of thumb is to anticipate the cutter deflection from the cutter rotation and stay slightly to that side. I did a video on this a while back. Thanks again.
Excellent work.Thank you
On the same principal, a person could just saw, file, grind, etc. A champfer to reduce load on the exit and eliminate the crater. As opposed to custom grinding an end mill.
The burrs which took you by surprise Joe were probably caused by the workpiece being very slightly 'out of square'.
There certain was a reason.
Just great video thanks
Great video Joe, as always. Would a ball nosed cutter work in the same way as the chamfered cutter? Or do you need to have a flat surface at the end of the cutter to work the way you show?
A ball nose would work, but a cutter with a flat bottom would give a better finish quicker.
Shear angle depends on tensile strength of the material... e.g Mild steel will be completely different to 4130
You are amazing!
Several people asked about ball end mills. What about corner radiused end mills? They have the flat bottom. I have a 1/2" with .125 radius which might do the trick.
thanks Joe
Hi Emma. Thanks for stopping by.
Yep acrylic is a miserable non forgiving material and will cut you like a razor blade. I hate cutting it with the bandsaw and can't wait to get it into the machine and lock the door! We do a similar solution with ball endmills. Thanks Joe!
As always, good advice. Just a question, how much does vibration from the vice overhang affect the finish, and do you have a 'rule of thumb' as to how much height overhang vs thickness is acceptable. I can get problems with melting, you don't seem to have this problem, mine is probably blunting of the cutter, any advice? thanks Tony
If someone really wants to see a cut and shear along with the rounded and burred edges just look at a heavy duty washer. One thing that always seems to generate horrible surface finish in the mill is slots and keyway. One reason is unless you can effectively blast the chip out from the cut is you will continually drag chips back through the cut. When facemilling I always tried to have about 70% of the cutter engaged in the work. Plus once you get so far into the cut you always have at least one edge or insert cutting. Plastics. Some stuff like acrylic I never liked. For the reasons you show here. Other plastics, Delrin for example, are always easier to cut. But they also seem to generate a burr just looking at the material. The worst plastic in my experience for burrs, as well as holding size is UHMW. You get burrs cleaning up the burrs.
When you were cutting the aluminum. From the metals I've worked with (aluminum, brass, copper, bronze, aluminum-bronzes, cold and hot rolled, stainless plus toolsteels). The worst for burrs are stainless, aluminum, copper and bronzes in that order. Aluminum castings can be really nasty to handle in a production enviroment. The same surface will have edges cut conventional and climb.
Drawn aluminum in the 1100 family is even worse than soft copper. Absolutely the worst gummy material I have ever worked on. that UHMWPE is miserable as well. Believe it or not, it deburrs like a dream with a piece of a broken light bulb. Try it.
great lesson, thanks
I learned something - thanks.
If it is the same pass, and chips fly from cutter deflection, can you predict the amount of reduction in size the towers will be after the second pass? Always learning. By the way you have the cleanest, uncut fingers I've ever seen on a machinist.
Marty B... in the shop that I work for we know what it will be usually depending on which tool we are using. I call this a spring pass where my lead calls it a tool pressure pass. I always keep my cutter approximately .002" from final and 99% hit it dead nuts with my spring pass. Every once in a while it can be more or less but barely.
I was thinking the same on his nails. 😁
@@TheFeller1554 I work with a lot of surgeons. If my nails are dirty just once, they will probably go elsewhere.
All the scars are under the callouses. Thanks for the compliment.
Marty Bernier Seems to me that the part should be the exact dimensions to the print after the second pass. Stopping after the first pass would leave improper part dimensions.
Sheared flat stock is always a dimensional problem and the thicker is the worse it gets. ( Rolled edge / burred edge)
When I had to shear sheetmetal I find that the burn from the shear has a taper on it. I believe it was due to dull blades. Chased it around for days before I was able to figure out what it was doing. Debuted parts after and they were better after. I hated having to run the shear.
They can be very helpful or create a huge mess.
I've never had much luck with poly methyl methacrylate unless I used a cutting fluid like 7-11 oil or a good water based coolant and then after machining I have to stress relieve it or else it crazes at all the machining points and to do that I need a ramping oven, so I prefer Poly Carbonate whenever possible.
PMMA is easy to chip. I've worked with it before. I like Delrin over all other plastics. Great to work with.
I don't know, Joe. I'm surprised the first pass in the acrylic when as well as it did. I was expecting to see divots the size of dimes coming out of there, assuming that the piece didn't snap off entirely.
I'm also a bit surprised you left the protective film on for machining. I've had problems with that in the past.
At any rate, I'd much rather drop acrylic in an Epilog or equivalent laser cutter. Much easier to deal with!
I would normally support a part better than that, but I wanted the part to jump around and make the example worse. If I pushed the feed harder, it would have emphasized the chips. As for the film, It didn't have any. Its got some surface scratches since its a drop part, so maybe thats makes it look less than pristine.
Piercing steel, at 10 percent percent clearance. You have about 1/3 shear and 2/3 break.
We use 10 percent up to about 100 thou thickness then clearance goes up to prevent double shear.
I’m trying to learn thanks for not being to technical. I watched a video where you stated as I Understood it boring bars on center turning tools a little over center So I was turning some bosses and did half of one on center and I he other half 35 thousands over center the difference was night and day on the finish thanks!
I usually shoot for everything on center as a rule, but if your tools are flexing, over center is probably not a bad idea.
Joe Pieczynski I’d love for you to see the part and give your take is any other media source your on that I could attach a photo
thanks for the info keep up the good work
Hi Joe, can you comment on vertical burrs if the final clean up cut is done conventional? It seems to me climbing will remove the vertical burrs but create a new, albeit smaller due to spring. Conventional should remove it completely I would think?
When I cut perspective I use a wood router bit,no craters or chipping
Hi Joe, great video.
Would a ball end endmill giver a similar result to your chamfered one or does it create it's own problems?
yes, but you'd have to make a hundred passes to get flat surface.
@@joepie221 Thanks for your reply.
So I gather when that when you chamfer the cutter you are leaving a small flat on it to get a non ridged surface?
It would be intresting if you made a video about how to cut gears.
I have very little call for custom gears here.
Awesome demonstration of climb vs conventional. With CNC instead of two identical passes, you often see two different passes. The first hogs out the bulk material, without worrying too much about tool deflection, leaving a small amount of material. The second pass is made with a sharp tool reserved for finishing, with speeds and feeds calculated for that remaining material. It's possible to use conventional for the first pass, and climb for the finish. You could do the same manually, but would obviously be a lot more work for the machinist!
What if you have an oversized tool on the acrylic such that the entire cut is always in climb, eg diameter 3x part width. How about a downward spiral toolbit?
Ian Danby Those are really good questions. Looking forward to hearing Joe’s answers.
A good trick for a CNC is to use the exact same code and exact same tool size for rough and finish, but enter a larger tool diameter for the tool you rough with. As for the left hand spiral cutter, I only have experience side milling thinner material with those. never actually milled like shown here. if you deck acrylic with a larger tool, one side will always be the 'Smear' side and subject to chipping. If you need a good part, support that chip side with another piece and let that one chip.
I used round stock acrylic to make handles my lath turned about 350 RPM , I drilled a 1/2 inch hole through , and if I fed the drill to fast the plastic would melt , to late to pull the drill out the acrylic would shatter and instead a handle ,I would loose a handle and 1/2 , I tried water and my three lower speeds but the best way I found is pecking slow but shore ...
Maybe try a smaller pilot hole first. Less friction=less heat on the final size.
I believe the solution is to grind a much pointier angle on the drill bit...
(Not a machinist, but I used to work with acrylic a little bit, and was provided with a special bit for drilling screw holes in acrylic)
On plexiglass I just leave 020 and make another pass.
Good plan.
Thanks for the video 👍
Ohhh Jaaa! Great lessons...
Hi Chuck. Thanks for stopping by.