CNC Milling and Heat Treating Blades for a PCB Separator | HotShot 360

in case you ever wondered this is what it looks like when you wrap it in m42 cobalt drill into d2 tool steel at 6000 rpm it looks for all the world like the drill partially liquefied before it went off to wherever it went and i had no idea that could even happen but apparently it can [Music] welcome back to cloud42 i'm james if you've been around the channel for a while then you will remember when i made this this is a hand pc board nibbling tool for separating pc boards out of larger panels and with some 3d printed parts and a pneumatic cylinder to turn it into a foot pedal operated tool so that i can quickly separate large numbers of pc boards out of their panels and this tool has been working great and it is still working great i've cut between a thousand and two thousand pc boards with it and i've been very happy with it however there are commercial tools that do this that are even nicer and they're normally pretty expensive but one came up on ebay recently and i grabbed it partly because it'll allow me to use different width blades for different pc board panel layouts and that's what we're going to do today is actually make a blade the right thickness for the panels that i cut but the other reason i wanted it is because it's a tool and i want to own them all before i jump in here i wanted to show these these were sent into the channel by robert and robert thank you very much these are cork coasters with my logo lasered into them and these things are great i will definitely be using these around the shop for one thing i'm not going to leave any more rust rings on my welding table perfect now this is the separator tool that i made and you can see this is just a simple little hand nibbler that was sold as a pc board separator for hand use but since i had thousands of boards to cut i 3d printed this framework and mounted a pneumatic cylinder to make this a foot pedal operated tool if you haven't seen that video i'll put a link up in the corner and you can go check that out if you're interested but this is the commercial alternative or i guess this is the alternative to this commercial tool this is called a sep 3 this is made by olemf and it consists of a hooked blade between what they call the matrix which is a couple of steel anvils that it pulls down between and it's all mounted on top of a pneumatic cylinder they've got a pressure regulator here so you can hook up a foot pedal and operate it so very simply it's just an air pressure actuated device and i can just put some air pressure with a blow gun into the ports pull it down press it back up so it's just a double acting cylinder and you slide the pc board with the little mouse here to be cut right here and it just snips it off you have that with a foot pedal you can just go chunk chunk through the whole board and cut them off rapidly so i've already looked at this and this is a used tool but it looks to be in very good shape let's tear it down and take a look at the blade the matrix is in two parts and they're just these little pieces of angled steel you can see there's definitely some wear there uh this is much softer than the blade so this is the part that's going to wear but in general a little bit of wear shouldn't hurt anything we might try to dust that off with a grinder and the other half looks very similar and then the blade itself is just held to the piston with a single screw and that is the blade let's see this one is 1.35 millimeters thick that is a little bit thin for my use so i'm going to need to get a thicker one for the pc boards that i cut now you can actually buy these from ole meth they're 100 or more per uh per blade and i'd like to get a couple of different thicknesses so it might be worth actually looking into making these in the shop so i did a little bit of figuring and i figure for materials and time and tooling we can probably make these for less than 10 times that price so why don't we go ahead and do that i've got some material this is the material i'm going to use this is d2 tool steel i've tested the hardness of this blade i've got my hardness testing files here and we'll just grab the hrc65 which is the hardest one that i have and it just glides nice and smoothly just makes a shiny spot on the surface doesn't cut at all so these are very very hard they're up around 65 hrc or harder and this material should easily be able to reach this this is d2 tool steel and so when this is hardened it should be very very tough it should be very abrasion resistant which is important because the fr4 pc board material this is going to be cutting is going to be very abrasive and it's going to wear and i want it to hold its edge so this material should be suitable and i think we'll just take it over to the cnc mill cut the parts out heat treat them and then grind them to thickness now i have never worked with d2 tool steel before from what i've read it is actually fairly rough to machine machinability around 27 which is probably one of the tougher materials i've worked with in the shop though i think if we have good carbide tools and we get the speeds and feeds right so we're not rubbing and we're not being too aggressive we really shouldn't have too much trouble we will see i am going to run the high speed spindle that i put on my g0704 cnc mill and so that might be a little tough to reach the slow speeds i need for drilling so i don't burn up drills but for an eighth inch carbide tool which is probably what we'll use to cut this out it should be no problem i have the part already modeled here in fusion 360 and i'm not going to go through the entire process but i will show you a couple of tips that make drawing parts like this a lot easier now i actually took a photo of the part and imported that and then drew the sketch on top of that photo and that's really easy to do click new design insert canvas select my photo and then select the plane that i want that photo on and it imports it but it's not the correct size and we can fix that by going over here to canvases we'll right click on the canvas say calibrate and then we can drag a dimension or come and click two points that are a known distance apart throw a dimension on it and then enter that dimension so i know this is 76.5 millimeters and now it has scaled that canvas to that size so now i can just come in and say create sketch select the same plane hit l for line and i can just start sketching out my part and i'm just going to do this roughly we'll come back later and put actual dimensions on it but i can then you'll roughly get my part to the right shape and you know this is fine for lines i'll come back and put dimensions to get them in exactly the right place but this is great for curves so i'll do a three-point arc here click these two points and then i can just adjust the arc to fit the photo and so then when we're done we end up with a sketch that's fully dimensioned in this case you know i followed the photo to get it in roughly the right place and then added the dimensions to make it exact and then from that we can just extrude the part and we are then ready to machine it now to machine this part we'll just go through the simulation here i didn't want this is pretty tough material and i'm going to be using a pretty small mill so i wanted to make sure i had good entry points so we drilled three holes first for entry and then just mill out the perimeter with an eighth inch end mill and then come back and bore and contour the insides of all the holes so it should be a pretty straightforward part to make let's export the g code and take it out to the mill i've got my stock cut to length the total parts about three inches this is just over three inches and we need to find a way to hold this but since i need to mill around the entire perimeter of it we can't really hold on to it with clamps we can't really put it in the vise without doing something really exotic so what i'm going to try is super glue and i've got a piece of aluminum here that i've already faced off i'm going to wipe down all these surfaces with 99 isopropyl and make sure there's no skin oil on there and then we'll just stick it down with super glue i already cleaned this once and then i came in here and touched it and this is a 99 isopropyl alcohol which i have hanging around all the time because it's used for 3d printing about a second to flash off and then i'm just going to use loctite 420 this is a thin ca adhesive and i'll just put on way too much put the part down and then weight it down and let it set and to weigh it down i'm going to use a 2 4 6 block and that should be plenty heavy we'll let that sit for a few minutes and set up and then we'll machine it it's been about 10 minutes let's see how we did i didn't glue my 246 block to it that's good and it's not even slightly stuck down okay this is not working let me grab some accelerator let's do this again with the accelerator this time so we'll put some super glue on there and i've got this loctite 7452 accelerator and i will put that on the opposing part and we'll try that again okay that has already grabbed tighter i'll go ahead and shoot some accelerator around the edges and i will go ahead and weight that down and we'll give it another 10 minutes it should be fine this time let's see if we did any better with with the accelerator i'm pushing on this as hard as i can with my thumbs because i really want it to break off now if it's going to break off it feels all right let's go ahead and zero up and start milling it and see what happens well that's interesting you can see the outgassing from the chemical reaction actually leaving marks on my 246 block i'll have to stone that okay the first tool in the program is a drill and that's tool 101 and we're just going to put some holes in this and where the internal cavities are going to be milled to give the the end mill a fighting chance to get in there set up the mist so it's got half a chance of getting in the right place and we'll give this a shot now unfortunately because this is such a high speed spindle and because we're milling such a tough steel i've got the spindle running relatively slow i think it's going to have enough torque to deal with this but there's only one way to find out let's give it a shot [Applause] okay that looks all right [Music] now the tool is going to do the most work here is an eighth inch four flute carbide end mill this one is a coated end mill from lakeshore carbide and we're gonna give it a shot if anything's gonna blow up this is where it's gonna go wrong i'm going to be running this at 6000 rpm which is about 200 surface feet per minute which is probably still a little fast for something tough like d2 but i think it's going to be all right as long as the super glue holds and as long as i've got my feeds and speeds right we should be able to cut this but again i should just stop talking and do it there's only one way to find out [Music] [Music] and sure enough there we go the super glue did not hold okay well let me regroup and see if i can figure out another approach here okay i tried something a little bit different this time i used loctite 414 which is a little bit thicker and i cut some grooves across the aluminum block to give the excess squeeze out some place to go i used the accelerator and stuck it down and it just grabbed a lot quicker so i'm hoping that this stuff works better than the 420 but there's really only one way to find out we'll just give it another try and if it flies off again we'll figure out what to do about that well so [Music] [Music] [Music] yes [Music] [Applause] [Music] okay and right there at the end while it was going up after the last cut it lost steps on z crazy okay let's see how big those holes are looks like the round holes came out about 233 and 232 let's call it and a small hole in the center for the screw call that 161 i will go and modify the program export the g-code and we'll just run those external perimeters on those holes again to open them up about six thousand take three thou off the wall and that's all just gonna be tool deflection here but i will do that and we will give it a run in previous videos where i've said i'll just go back and take a few more thousands off one of those features i've had people ask in the comments how i do that so i figured i would show that so i've got my setup here in fusion 360. here are my operations and i have already posted this and so i have my nc program here it happens to be called nc program two it was just the default it was given and so if i modify these and then repost it'll regenerate this program and that's not really what i want i really want to create another program that just does the recontour so i'll come in here on this main contour i will right click and i will say duplicate and it will create a second one which i will call recontour and then we will edit that first thing i want to do is come into the geometry and i'll control click to take off the perimeters i don't want to cut i just want to cut these two holes bigger and so we'll go over here to the passes tab come down to stock to leave and we'll axial stock till we will set to zero and then radial stock i want to make this uh and i want to take an additional three thousands off of each wall so i'll say minus .003 okay and now that will generate a an operation that will just take three thousandths off of that wall so now i can come up here and say post process and this will create a new numerical control program and i'll call this 1002 recontour and over here on the operations tab i have because i had that selected when i chose the pro to create the new program to post it it's selected but i can select exactly which operations i want in this and i can leave just that one recontour operation there click post and it will then generate a new program that has only that one recontour operation and then that recontour operation appears up here as a new nc program which i'll also call recontour and so now i can go back in and modify that if i want and regenerate that program if i open up the initial program you can see that this new operation that was added recontour is not turned on as a part of that i could turn that on or i could modify or do whatever i want with this and so generally what i'll do is i'll create the recontour once i get that dialed into size and just redoing that one operation until i get what i want then i'll go back and modify the original contour with the same parameters and repost the original program so i can use that to make more parts that are already the right size and don't require the recontouring [Music] we should be looking for 238 on this hole and we're actually a little bit over so took out a little bit more of the spring how far over yeah about 239 so we're about one thou over there the small hole should be 168. and it clears that easily it's just a clearance hole for a screw 169 doesn't quite go through so we're actually in just about the right place okay that is the part milled to size okay now that the part is made the last thing to do is to separate it from the super glue and to do that i've got a torch and we'll just heat it up and that should break the super glue bond and it should come right off [Music] don't really know how much is going to be needed but that's it and these parts are the result they look pretty good i'm i'm pretty happy with these now i cut the one on camera and you got to see that you got to see that i had a little bit of trouble with the super glue and i continued to struggle with the super glue i think this one popped off twice and if you look very closely you can see that this center hole is very slightly out around and that's because i drilled the holes and then it broke free and i put it back on and finished the machining and there was enough margin everywhere except that hole but that's just a clearance hole for a screw so it doesn't matter at all and then you can see that i cleaned out the corners on these so that they are nice and sharp inside with a very small radius and they match up to the original part very very closely in fact it's it's pretty much a perfect match except for the thickness so these should now be ready to go uh i did have one mishap uh if you you may have seen this on instagram this is a little scrap of one of the parts and what you see there embedded in that is an m42 cobalt drill i had it spinning at 6000 rpm started the cnc program and it was the wrong code i actually had the code from the recontour still loaded when i went to make the second part and so it tried to plunge down thinking it was a short end mill and it was not it was a long drill and it has embedded that drill and actually it looks like partially liquefied it into there and that is now a permanent part of this didn't penetrate the tool steel i have never seen a drill do that before i would have expected it to just snap off which it eventually did but not before really mangling and embedding that m42 cobalt material into this part i'm truly impressed with that and all i was able to find in the end was the tiny little stub of the drill that was still in the drill chuck everything else is either in here or completely gone now to heat treat these these are going to be treated at 1850 fahrenheit that's pretty hot i don't have a lot of excess thickness here to lose to oxidation i don't want to do a lot of grinding so we're going to enclose the parts in stainless steel foil and this is just a type 321 so technically it's low temperature good to 2000 degrees fahrenheit which we'll do for this and this i just got this from mcmaster carr and uh comes the little seam roller nice if and or when you work with this stuff know that it is very very sharp so hmm okay i'm just going to go squeeze the end of this in the vise okay that gives me a nice neat little packet sealed on the sides and the end i've bent up at about a 40 degree angle maybe a little bit more and that'll give me something when this is in the furnace that i can grab onto to take it in and out this is my heat treat oven this is a hot shot 360 made by stan over at barzee industrial this is one of the early models that he manufactured in his shop prior to these being sold by american rotary under the american kiln name this one has the n480d which is the ramp and soak controller and i have it pre-programmed to ramp up to 1400 degrees for a preheat over the course of an hour then it will soak at that pre-heat temperature for 30 minutes then over the next 30 minutes ramp up to the heat treat temperature of 1850 it'll soak there for half an hour and then power off so the entire process is what a two and a half hour heat treat cycle because these parts are so thin that's probably overkill but that's quite a bit faster than the five to six hour cycle recommended by the manufacturer now i've got the oven cold and i will just put the parts in here on a tile where they'll be easy for me to grab and get out later and then we'll just start the program it will program yes run yes go enable the heat and the bottom temperature is the set point so that's 62 63 64. that's slowly ramping up and then the pid controller will engage the elements and track that curve and we'll come back in a couple of hours when this is ready to quench now d2 is an air quenching tool steel so you can just pull it out and just let it cool in still air and it will harden but i'm going to use a technique called plate quenching i've got a couple of pieces of aluminum these are an inch and a quarter thick and so there's a quite a lot of aluminum mass here and i will pull the aluminum foil pack it out or the stainless steel foil pack it out still in the packet set it here set the other one on top and clamp it down and that will do two things one is it will suck the heat out rapidly without ever exposing the parts to air because they'll still be in the packets and the second thing is because the parts are clamped between two flat surfaces it'll be very difficult for them to warp it'll hold them in place and this is a common technique that's used for knife making this is all brand new to me i haven't done this before so we will see how it turns out but i'm hopeful i've got a thermocouple taped here to the this top block of aluminum just to see how warm they get and i've got that on my meter here and so when the time actually comes to quench we can see how much the temperature rises on this on the aluminum parts the aluminum is going to stay pretty much one temperature because it conducts heat so well so this will give us a good idea of just how much heat's being sucked into these i'm guessing the temperature is not going to change on these much at all okay this has been running now for about two and a half hours and we're at 18.50 and we've been soaking at 1850 degrees fahrenheit now for about 30 minutes so okay clamp between the blocks and you can see the temperature is already rising because aluminum is such a good conductor up to 80 degrees fahrenheit already and i can feel the heat going in there the fan on the oven is going to continue to run even though we've turned off the heating and that's because the fan is just cooling the electronics box okay and now you can see that the temperature of the aluminum blocks is now starting to drop i can just barely feel the warmth in it now and so i think the quench at this point is pretty much done but we'll give it a few more seconds [Music] yeah even the foil here the sticking out the side is cold to the touch [Music] yep barely even warm to the touch okay let's open it up there are the parts they look flat and they look straight see how hard they are just for comparison this is the material that we started with which is this is the lowest hardness file i have the hrc40 and it easily is digging in and grabbing but on the heat treated part yeah that just skates and here's the high end the hrc65 yeah it just skates without without digging in also okay these need to be tempered and then they need to be ground to the final thickness i'm going to temper these in the kitchen oven i'll just put these in at 400 degrees fahrenheit just set them both on a tile put that in the oven at uh in a cold oven or i'll probably put in a warm oven uh temper these at 400 degrees fahrenheit for a couple of hours then just turn the oven off and let them cool and then we'll be ready to grind now i don't actually have a surface grinder yet so i'm going to head up to my friend uchill's shop up at woods creek workshop and he's going to help me grind these that's not going to happen today but you will see that in a future video scratch that you're going to see it now through the power of prior planning these blades are now ground and ready to go it's been about a little over a week since i heat treated these and in that time i flew up to woods creek workshop and spent the day with uchill grinding blades and eating noodles and it was a great time there is a video on his channel with the entire grinding process i'll put a card up and a link in the video description definitely go check that out you can see the grinding process and while you're there check out the other content on his channel give him a sub it's well worth it i got to see in person some of the stuff that he has made and the workmanship is just superb it's it's well worth the subscription anyway these are ready to go let's talk a little bit about uh what i learned in this process first thing i learned is that d2 tool steel is very tough i mean i chose it because it's abrasion resistant but that became really clear when grinding it as long as you keep the wheel moving you take in two tenths maybe a quarter thou at a time everything went great but if you slow down even for an instant the wheel will grab slow and dig in and this little beauty mark here is all the evidence that's left over that we couldn't completely grind out without going below thickness for one of those incidents as long as you keep it moving it grinds great we were grinding without coolant with an open structure wheel the parts were staying nice and cool but you definitely need to keep moving the other thing that we learned is that this d2 steel at least the way i heat treated it had a lot of residual stress i don't know if that's because of the plate quench because it quenched so quickly or unevenly as opposed to an air-cooled quench which is what d2's usually intended for but what we discovered is that as you grind material off of one side the part started to cup to that side so if in multiple passes you took it down two thou and then went and put that on the surface plate you could put a one or two thousand feeler gauge under the middle of it because it bowed that much but then if you flip it over suck it back down on the magnet flat take the same two thou off the other side it straightened back out so as long as we took the material off evenly the part stayed straight certainly straight enough for this application and you know since it warped a little bit as we were taking material off i was a little bit worried that maybe it had only been surface hardened but looking at this afterwards with the hardness files this is the hrc65 file they still just skate beautifully over the part without digging it at all so they were through hardened there's no need to worry about that let's put this thing together and see how it works that fits nice and neat on the alignment pins just a little bit of play just like the factory original okay that's the hook slide matrix in here on both sides and that should be that let me grab some air and make sure it cycles beautiful i don't have any pc boards to cut let me grab something what do i have that this would cut it's a piece of pc board material but it's not it's not perforated so it probably won't cut through this but let's see nope oh yes look at that oh yeah i will definitely want to use this with uh pressure regulator because that just sliced right through it not even perforated okay i'm to call that a success and i think we are ready to go next time i have a batch of pc boards to cut well if you enjoyed this video give it a thumbs up feel free to subscribe to the channel and leave me a comment i'd like to know what you think have you worked with d2 tool steel have you experienced warping do you use plate quenching do you use air quenching let me know your experience i'm always looking to learn and definitely go check out woods creek workshop and check out the video on youtube's channel and some of his other stuff while you're there thank you for watching [Music] you

Channel: Clough42

Views: 11,799

Keywords: SEP3, HEKTOR2, Heat Treating, D2 Tool Steel, CNC Milling, Milling Machine, Drilling, HotShot 360

Id: PRHeVU2YCgU

Length: 39min 35sec (2375 seconds)

Published: Sat Dec 18 2021