CNC: Low Budget Shrink Fit

Today we use 2700 watt induction heater from ebay to shrink end mills in and out of shrink fit tool holders

[@user-tw9io9nz2m]

I work in the tube and pipe industry and design parts for tube mills. One thing I deal with are industrial scale induction heaters, they are used to weld the tubing in line as it gets formed. A very important parameter is the frequency at which the heater switches current (all induction heaters work on AC). Frequency dictates radial penetration depth of the heat into your part. The higher the frequency, the shallower the depth of active heating measured from the outside in. In your case it’s desirable to turn the frequency all the way up so the heat gets to the tool as slowly as possible. Your unit cannot go too high, you would need to go above the megahertz range to see a drop in efficiency. Speaking of efficiency, since you use a relatively low powered unit efficiency matters. The strength of the switching magnetic field which causes the heating weakens squarely with distance form the coil. This means you will see great benefits by making your coil fit around your holder much tighter than you have it now. If you’re afraid to burn your insulation you can use glass fiber wrap if you have easy access to that or if you want permanent coils you can try a ceramic dip, nothing fancy just basic pottery stuff. We use a teflon sleeve but our coil is cooled through and the moving pipe doesn’t radiate much heat unlike your stationary tool holder. I would also recommend removing turns from your coil. A turn or two short from the overall length of the part that needs heating. An overly long coil is just wasting power. Induction heating can seem like black magic but these simple guidelines should help you improve your setup, feel free to ask if you have questions about this

[@ikbendusan]

i doubt he's got control over the frequency this thing puts out lol. given that the induced current is going the same direction throughout the part, and that there's a hole in the middle, wouldn't the skin effect at cause the outside *and* the inside to be heated? (like this: i.imgur.com/FZyWTw1.png )

[@MysticalDork]

These smaller heaters are self-resonant - They have no way to control the frequency.

[@SuperYellowsubmarin]

You absolutely want to avoid heating Teflon ( or other fluorinated polymers) over 200°c, it will smoke toxic fumes.

[@user-tw9io9nz2m]

@@SuperYellowsubmarin the teflon in the process I work on does not get hot and even if it did there is an enormously powerful centrifugal extraction system that sucks up everything from smoke, streams of coolant and even solid chunks of material if they happen to fly by

[@kravselj]

Hi, I bought 2000w zvs heater for diy shrink fit and it works great, except in I put whole tool holder in the coil it draws too much amps, so overcurrent protection kicks on. Basicly the larger diameter I put in the coil more amperage it draws. Having little EE knowledge I wonder if making similar coil with same number of turns but larger in diameter would help. Or maybe just taking a turn away, now it's five turns.

[@Agustin-jo8mv]

Awesome! I really like this channel for 3d printing and CNC stuff. Thank you for all of your hard work.

[@EmperorDevilhunter]

I had this in mind a while ago but wasn't sure if it would had enough power, so I just went with a torch on my DIY TTS shrink fit holders. Knowing that it works, is a great addition to a semi profesional shop. Thanks for sharing.

[@kentklapstein9879]

Just found this video. GREAT stuff, I did get set up to attempt this last year but did something dumb. The cheap ebay induction coil I bought had a bare PCB with exposed terminals on the bottom. I shorted the whole thing out when I placed it on a steel table. This video motivated me to try again. Again great video, great!

[@85CEKR]

a small manual lathe and one of those butane torches works great and you don't have to worry about uneven heating or cooling. We do a lot of 1/8" heat shrink tooling that way and I can do a tool change in about a minute and a half including cool down with an air gun.

[@davidlawrence8085]

Craig thanks for your dead-simple & inexpensive approach..... Love the idea of spinning it...I imagine you will say it doesn't matter but about what RPMs do you spin the manual lathe?

[@85CEKR]

@@davidlawrence8085 hi David thanks, I just spin it at about 50 rpm. I don't think there's any benefit to going faster (also I don't like to clamp the tool holders to tight so they don't get marks on them)and that way I can stop the spindle quicker to take the old out and put the new in.

[@robertqueberg4612]

That is a good idea, if you have a manual lathe in the shop. Sadly, these seem to be getting scarcer each year. The propane torch heat source shows good smarts.

[@ericblenner-hassett3945]

Looks like a breaker for the switch, great idea! Any short should kill power and least amount of ' magic smoke ' let out! Great video, great precautions, have a great new year!

[@Cncfallstar]

the last parts was so amazing thank you for giving us information and entertainment keep up!

[@cobraframebuilding]

Merry Christmas to me. Thanks for the video!

[@boboconnor1403]

I liked your high tech depth stop while putting the mill in, lol.

[@andrewh3141]

Pretty cool set up man! I used to set shrink fit tools using a very expensive Zoller tool presetter and it looks like you’re cooking your tool holders. I’d recommend holding the end mill as the holder is heating and every couple seconds check to see if it will slip in. The second you feel that it will slip in, turn it off. Overheating them will reduce the life of the tool holder! Just thought I’d let you know, take it easy!

[@NerdlyCNC]

Andrew Henry thanks Andrew. Will do.

[@seanbosse]

Excellent idea. Thank you for sharing

[@aronandreas]

I just love it... 😊 Biggest smile from Norway

[@robertqueberg4612]

Your heater seems to work nicely. Congratulations. Now for the Dad lecture. Throw those gloves with the synthetic(sticky when melted) materials in a tool box, away from hot surfaces. Hot mill or welding gloves would be a safer choice. Also consider what would happen if you step on a piece of hot slag from a welder or cutting torch while wearing sneakers or any thin soled shoes.

[@cobraframebuilding]

I bought the exact same kit from the exact same seller. For wiring to the power supply, the terminals are labeled ground, N and L. To get into the 200-250v range I would need to go Leg-to-Leg, not just Leg-to-Neutral. Is that what you did? I'm wary to wire voltage to a terminal labeled for neutral, but that seems to be how you'd have to do it. IIRC my shop is 208v 3ø where any L-N is 120v and any L-L is 208v. Excellent video, and thanks for your contribution!

[@poetac15]

Curious to hear if there are any better options on the market now that a few years have passed. The shrink holders are super affordable so making a unit like this is very appealing.

[@chucka103]

Thanks Jason, I,m gonna give it a go.... finger crossed cheers

[@Evotechcorp]

Building a similar project using an off the shelf 15kw power supply. I would recommend adding a foot pedal control that does 2 things -#1 throws the contactor to energize the unit and #2 controls a pneumatic valve to actuate a cylinder for raising and lowering the coil. If you want to go a step further get a multi-position valve with a timer that initiates an air cool down cycle. Not a fan of using breakers as an on / off switch, they're not really designed to be cycled repeatedly.

[@mikeberlinquette9896]

Awesome job

[@Nutzernameungueltig4]

Hey Nerdly, thanks for this video! Do you have any updates on this?

[@joshuahuman1]

great video i would love to see a video about upgrading it with a stepper

[@timramsay2995]

Paper clip trick! Good one!

[@stonecraft745]

You are insane!! This is a big thing!

[@revolveperformance]

Awesome. Im building one!

[@ruftime]

So cool!

[@chaddanylak8706]

I think you letting it to heat up to long , what I normally do is turn on the heat shrink machine, and hover the bit over the holder until it slips in, what I been told is that you can damage the tool holder if you over heat then for too long you could use a Arduino with a built in timer to prevent overheating

[@user-tc2ky6fg2o]

You are right, that holder which heated to red is probably damaged. Not only the micro structure (hardness, etc.), but probably deformed as well loosing accuracy (which was aimed by the shrik-fit). You need a thermometer (or thermo camera), not (only) a timer to control the temperature, and do the homework to calculate or look after the right temp. You can use the damaged holder to calibrate the process. Otherwise congrats to your machine! Maybe a little bit smaller diameter and shorter length coil could concentrate the energy to the place where only needs to be heated.

[@andrewgutierrez241]

Do you have a parts list or links for this setup?

[@TommiHonkonen]

rego fix have nice and easy similar type system, but its expensive too.

[@RobertSzasz]

Oh, and are you powering the nice big fans on the induction driver separately or are you killing their power as well as the main power for the induction circuit?

[@NerdlyCNC]

Robert Szasz it comes with a power supply for fans / coolant pump

[@capnthepeafarmer]

J on professional heat shrink machines you have a much smaller coil that is smaller in diameter and smaller height. You also want to stay below ~500f, never go above blue temper otherwise you're going to get some oxidization on the holder.

[@NerdlyCNC]

capnthepeafarmer thank you

[@MysticalDork]

Not to mention if you get too hot, you'll start to mess with the heat treatment of the tool holder.

[@MrEpicLion]

Crazy seeing you here!@@MysticalDork

[@ciscohernandez4384]

Hey Nerdly, do my search skills suck or did you take down some of the videos you had recently uploaded. I saw you posted a video on how you got started. As a new shop owner, I was looking forward to taking a looking, or did I just dream that? hmmm lol

[@wymer999]

what brand tool holder you using?

[@cobraframebuilding]

Do you intend to use the water cooling? Is that just for continuous duty use?

[@NerdlyCNC]

Cobra Framebuilding yeah I’ll set it up. Not sure if it’s really required for how infrequently I’ll be using this.

[@magicman9486]

ok that was cool!!!

[@RavenRockMachine]

haha "Shit..." Great video buddy.

[@RobertSzasz]

Are you running cooling water through the induction coil? (And did you tune the coil or are you running as supplied and they should have tuned it?)

[@NerdlyCNC]

Robert Szasz not yet / as supplied

[@ReiniGrauer]

@@NerdlyCNC Do you know if reducing the number of loops in the coil would concentrate the energy to a smaller length? I'd love to get some shrink fits on my new Fadal and was looking at doing something just like this.

[@ikbendusan]

@@ReiniGrauer yes it would

[@MysticalDork]

@@ReiniGrauer Yes, to maximize heating it'd be best to shrink the coil in both diameter and length - The closer the better, because magnetic field strength drops off with the distance cubed - Double the distance, 16 times less field strength.

[@MrJTJINX]

come on J, you have loads of time its not like your building a Jonny 5 or anything lol.

[@rallen7660]

I think it might be a good idea to invest in one of those $25 infrared thermometers. Let you know when it's hot, and when it's not. Know what I mean, Vern?

[@ashleyaewells]

R Allen They don’t tend to be very accurate on shiny metal, the best method is to gently hold or pull the tool then it will move as soon as it’s hot enough

[@dmyegorov74]

Great job. Wondering if the same can be done with 2kW and 110V. Maybe will take more time but for a hobbyist it isn’t that important.

[@NerdlyCNC]

dmyegorov74 you may not be able to get end mill out of holder

[@dmyegorov74]

Nerdly i think power of the heater only affects how soon your tool holder and end mill will reach certain temperature... if carbide has lower temperature expansion than steel, you just need to reach certain temperature of both to take your tool out of holder... less power you have, the longer it will take... so i guess 2kW is good enough unless your room temperature is too low and the surface area of your tool holder is too large to dissipate the heat you are trying to induce into the holder

[@NerdlyCNC]

dmyegorov74 I agree. But heat soak is a problem

[@dmyegorov74]

Nerdly a little covered box with a door around the area can greatly reduce heat loss. I’d try a $50 induction cooktop from amazon with a modified coil.

[@MysticalDork]

@@dmyegorov74 Heat loss to the environment is not the issue, the issue is heat transfer from the tool holder, to the tool - Even though carbide and steel have different coefficients of expansion, that is often not enough to get the tool out of the holder at a reasonable temperature, when the tool and the holder are the same temperature. That's why it's easier to get the tool in, than it is to get it out - when inserting, the tool is at room temperature. With a commercial system, the heating is localized to the holder only, and is fast enough that by the time the holder is at ~500F, the tool is only maybe ~200F. That extra thermal differential is essential, especially if you want your tool holders to last a long time, by not heating them to a ridiculously high (glowing red) temperature and changing the temper of the toolholder.

[@qqqqqqqq1407]

The amount of extra time you have makes me wonder how many hours do you actual make parts at ur 'job shop'?

[@NerdlyCNC]

petiyo101 I don’t own a job shop :)

[@qqqqqqqq1407]

@@NerdlyCNC well then what do you do there?

[@paulanthony873]

not getting notified of you’re new videos

[@owievisie]

Haha that’s dope

[@rc-cnc3431]

Ooops :)

[@machinist7230]

I think you overheated the holder - they dont require that much heat to get them to open enough to drop an endmill in.

[@NerdlyCNC]

yeah maybe.....ive seen guys get em cherry red with a torch...it'll be fine and if it isnt...i'll buy a new one.......its the price of an education

[@KingCoopa69]

@@NerdlyCNC ya it looks like u toasted that holder. we use haimer heat shrinks and we never got them that hot usually hit them for 5 to 10 seconds and that was it. I would not recommend hss for heat shrinks unless index cutters

[@johnhansen1684]

@@NerdlyCNC ye looks like you are overheating it abbit. but ye its true you wont destroy the holder even if its red hot. but i belive its bad practice. what i like to do is to have a tool in the holder and heat it wile i pull on the end mill and when it realese i note the time. I got some thin Haimer shrinkfit exetensions red hot and measured to see if there was any run out. and it was still like new.

[@machinist7230]

@@johnhansen1684 i think the issue with over heating is it reduces cycle life dramatically. One of those relays with built in timers might be a good idea here.

[@ikbendusan]

pretty sure that's infrared that the camera is able to pick up bro

[@BaldurNorddahl]

Why not a hydraulic chuck tool holder? I found some pricing here www.cutwel.co.uk/tool-holding/bt-mas-bt30bt40bt50/bt-mas-hydraulic-expansion-chucks/bt30-1. It does not seem to be that bad compared to shrink fit holders and you save the cost of the induction heater.

[@NerdlyCNC]

Baldur Norddahl I guess you didn’t hear me say I need clearance for 5 axis

[@BaldurNorddahl]

@@NerdlyCNC Some of the hydraulic options are just as slim.

[@NerdlyCNC]

@@BaldurNorddahl for .125" end mills?

[@BaldurNorddahl]

@@NerdlyCNC well sure although I believe you are supposed to use a sleeve to hold very small tools. Something like this: www.kennametal.com/en/products/20478624/2664259/42025689/42025693/54449232/100018496.html I am not claiming to be the know it all. In fact I just got a small hobby CNC mill with BT30 tooling and I am happy with ER collets. It was just that you said shrink fit was the hot thing and I thought it was actually hydraulic that all the cool kids are bragging about now. From a pricing perspective it appears that if you only need a few holders, then hydraulic could be the cheaper option, because you save procuring the heater. If you need a lot then the simple shrink fit system will win cost wise.

[@Mtaalas]

Using a breaker as a switch is definitely not recommended. The contacts are not designed for DC-current so it can arch too much, and that'll ruin the contacts or better yet, doesn't cut the power when you need it to. What's more, that setup isn't stable so you're adding unnecessary risk of getting electrocuted by not having things bolted down. You also don't want ANY live parts that you can even by accident touch etc... I can see there plenty.... don't :D

[@platin2148]

I though APC was one of the nicest things that you can get..

[@danarrington2224]

You should never use a micrometer to measure your gage blocks. Especially if your mics are carbide tipped. Over time it will wear the blocks unevenly. I've been scolded for that many times from old-school tool makers.

[@NerdlyCNC]

Dan Arrington lmao. I’m not sure what else I’d measure them with. And this isn’t my $1700 mitutoyo set. It’s a $150 set

[@danarrington2224]

@@NerdlyCNC I said the same thing. How do I measure them? I ended up buying a cheap set for myself so that I wouldn't get chewed out for doing that. Their answer is that each block has its size engraved on it. Just do the math.

[@NerdlyCNC]

Dan Arrington lol. I was using it to ensure mic was dead accurate.

[@horvathcsaba1265]

The measuring force of a micrometer is around 12-14 N. I have no idea how that would damage anything unless you scratch it. Great content as always!

[@danarrington2224]

@@horvathcsaba1265 That's the reason. The carbide will scratch the surface of the block.

[@ashleyaewells]

Hi Jason Try making a smaller coil for it, mine is 3/16 tubing wound around a 50mm bar. heats my holders in roughly 12 seconds, just be careful going too tight as could overload the unit. Here's some clips off my phone of mine working: kzbin.info/www/bejne/p4O0qZpsprSZe7c

[@1pcfred]

Shrink fit tooling manufacturers hate him! The one weird trick that lets you avoid the high cost of their machinery.

[@octapc]

Too be honest I don’t know how this is utilised.

[@frp1276]

kzbin.info/www/bejne/f3axdo2tnpqkhtk

[@octapc]

FRP Thank you for the link. Made it clear.

[@jirisohr3267]

8years later ... Nothing new.

[@tiffanysmin]

Hey Jay! How do we go about getting a product reviewed on your youtube channel? Thanks! DiabaseMachines.com

[@NerdlyCNC]

Tiffany Min feel free to email me : [e-mail]

[@krazykillar4794]

Respect 👍