Machining of an assembly fixture

[Music] hey welcome back was quite some time until the last video so I'm working on these parts for customer 7075 aluminum and this has a whole bunch of features on it that our first glance look very complicated but when we machine it it's just step-by-step machining and I want to show in this video help break down a very complicated part at first land into a series of very simple machining operations so I already machined as part on the lathe out of a piece of round stock turned down the shoulder and finished this OD chamfer that then I took the the Chuck of the lathe took it off the spindle mount dropped it into Iceland here on the milling machine and I cut these flutes now we have a bunch of precision located holes in here and those are referencing off the diners here so I'm really cating I'm just double-checking that my mill spindle is still centered over the part under the fluting yesterday and I'm back to do all the other features so thermal creep and whatever could have shifted the precision of the spindle to the part so I'm just indicating in and looking for those possible deviation on the needle and I manipulate the XY table of the mill to get it to zero and that it creeped it moved probably point oh one millimeters so I'm referring my dro here I already have a small three millimeter starring starter drill and see started grilling and I call it Chuck and we will drill three holes here here and here and that will get drilled through Sri Mahmoud and get a very large countersink okay setting the Dro for the bolt hole the hole pattern it's this button down here pitch circle diameter in XY plane position is zero zero at the center of our part diameter of the bolt hole circle is twenty nine point six millimeters starting angle yes according to print at zero and angle as we were doing a full circle is 360 and we want number of holes we want three holes but with this dro if you put in three you would have to calculate the end angle yourself and that doesn't make sense you can do it but it's extra step so if you put one hole more the number of holes you want to drill plus one you can just leave 360 as the end angle and they're kind of makes sense there we go then says number one at fourteen point eight so now we just crank the table over until we have a zero here there you go also what I do when I want to locate the table often milder precisely I will go until I have acero here cero and then I will back off the handwheel a little bit so I take off the pressure off the lead screw so the table is now just sitting by its own in its position and it will not lock the table locks because those can't shift the table too otherwise if you leave the feet screw under pressure it can table can't creep for example when you get the vibrations when you start up the motor of the mill or bump the table just by walking by I mean like that okay first hold position spot drilled now we go to hole number two now we change to a three millimeter drill we switch show countersink this is an uneven divided 90-degree countersink you can see that this portion here is way narrower than this and this and that leads to a very very nice very smooth running tool without a lot of chatter they are fairly expensive though most tooling suppliers should have those in stock I prefer them this style of canta canta think over the zero fluid or the six flew style any day for me it's these or a single flute debate style countersink and these need to have a diameter of 10 limit at their large timeless are just using a scale and it will also notice that I have it running very slow this is form tool we have very high engagement the cutting edge is so if you want a chatter free result go slow or run it fast and for very high feat pressure but on a manual machine that sometimes not possible it obviously leaves a burr here at the exit but we will clean that up by hand later not now okay we have to drill one more feature here this is a stepped hole we've come to think this one is not on a pitch circle diameter it's just an XY coordinate offset from the center for this part I didn't get a drawing I only got a 3d solid model and I imported it in fusion 360 and I pull all my dimensions out of it and I created the drawing for myself a shop drawing and see starter drill putting in starter hole okay I have to use an A or eight extension in my er 16 check so I can clear this boss of the part in the center and do not have to extend the drill out half a kilometer it's a one point two millimeter drill bit 47,000 diameter 4 inch speaking through such small tools it's a good idea to indicate them in just put an indicator up against it and spin it by hand and check do you run out off the two foods you're looking for the two high spots obviously got zero and zero so obviously I already bumped us in because we have a horrible tolerance stack up we have the er 16 we have to be are 8 we have to call it we have to drill bit drill bit is possibly not straight to so good idea to indicate it and the way I do this or like most people do it they take a soft faced hammer or a copper drift and they bump the nut on site like this and that shifts the nut which has to call it taper the front color taper in it slightly over within the range of the clearance in them and they're not and the columns read and changed your intuition of the collet a little bit and that changes to run out too has its limits works only works better with standard style not select this one up here which have a course of threat and these have a little bit more clearance on the threads the fine threaded ministry nuts down here do not react as nice as I would wish they did when you you hit them on the side and expect them to move and stay that way piece as long as you do not have a roughing and you bump them over they will stay in that position during machining okay counter boring with a four millimeter carbide end mill three flute four millimeter deep you [Music] [Music] this is the template table of the pantograph machine and i milled out template out of five millimeter lexan three times larger than the actual part with the contour we're going to cut onto the aluminum part it has a six millimeter hole board in position that actually is the center of the part all done in cat which is way easier and laying it out the hand and I have to stylus off to pantograph in this war and that means that I can use the spindle of the pantograph to Center my part by moving the XY table six car truck is on the way in device of the paragraph mill and I have my indicator holder plant in the spindle and I use this to Center the spindle over the part the nice thing with having it then the Chuck is that it doesn't lose its orientation its angular orientation because I have two flats milled on my my back plate of the Chuck robin Renzetti showed this is one of this videos to have two flats that you can use to clamp it in and I wise this is super useful I use this all the time to take tape machine apart take it off the lathe go to the mill or another machine and finish it there quite neat and yeah I'm indicating part in moving the the XY table around I'm centered already lock all my axis and zeroed out the dials and ok I can change the two millimeter and middle and cut this feature I'm using a long two millimeter carbide end from Mitsubishi carbide twelve millimeter neck so I can go down 12 millimeters with the small ant mill which I don't need I think we have to go down nine millimeters this case but that's what I have here okay well the contour work is done here on the pantograph machine now it can take this part finally out of the Chuck clamp it on the collet and paste off the waste stock on the backside we're done so first part all operation from backside are done turned the inside next will be we have to have a slot here on the side but the slot obviously has to be orientated in respect to all the other features on this part there is nothing to indicate if we hold it like this in dividing head so I made this little alignment jig it's just a piece of tool steel I turned a very shallow step on it with the ID of this part so this can slip over this very easily and I have a single three mil made a dowel pin that goes in one of these holes and two m3 threaded holes so part slips over the dowel pin that's your first alignment then it slips over this large Center diameter and that's your second constraint that Orient's the part and we put in two screws chew em sorry countersunk screws flathead screws it doesn't need much torque we don't want to to mess up the aluminum and the other dimensions of this part or ground Square and flat so when I hold this like this in the dividing head I can just run an indicator along here and rotate the part until I get this surface here horizontal then I have the right orientation then I can use indicator and center my y-axis on this Jake Center it then I have my syrup point where against - machine on my slot it's as easy as that we could do it in another way - we could yeah do you do you couldn't do much to indicate this part when it's horizontal and indexing head this is my mind the most sane solution especially as I probably have to make a few more of these parts than this jig will pay off very fast especially as I have one last operations where I have to stand part up like this and drill to one millimeter holes for dowel pins we're back on the mill I have to part and on ER 25 collet Chuck in the rotary table and I'm running an indicator along the top of my alignment jig here and as you can see it's not it's not really in line with the travel so being a rotary table I can of course adjust it very precisely and I just moved back and forth and tweaked the rotary table until the needle doesn't move anymore yeah that's pretty good that's that's less than 0.01 millimeter over over this distance this is 36 millimeters yeah that's pretty good let's lock the table the rotary table so it can shift recheck it obviously the locks on this erodible are not not influencing when I tap this down I I move the table a little bit very my new the mount the now can get the indicator out of the way set up our part and we're good to go to cut out the slope and edge finding the interface of the jig which is also the face of the part in this direction we have of course take the diameter of the edge finder into account I'm starting with a 2.5 millimeter end mill to rough out the slot and then I will change to 3 mil middle and finish it to final size if you try to mill a 3 millimeter wide slop with a 3 millimeter end Miller right away it will look quite ugly because the full slug and cut will deflect the cutter and in this case I don't want that okay there we go now we change to three moment milk sweet sugar which is more rigid to begin with and special purpose for aluminium again touching off on the top of the jig from where I I took my depth dimension and cat oh when you touch off with an end mill on the part be super careful or you will chip the end of the flutes especially with carbide end mills and with animals that have a geometry for aluminium because those are ground to a more acute angle and therefore more fair child what I'm going to do is I will plunge down to full depth on both ends of the slot to create the the end radii and then I will step then I will take down out the middle step by step okay I use a flip the rotary table down on its back now we're back in a horizontal position I used to Jake to align the part with travel off the machine again and now I'm double checking if the location of my bore meets up with everything else I moved the table over to the XY position of the hole put in a one point two millimeter pin in fact it's a drill shank because my gauge pins are about five times longer and I'm using the dial test indicator to check if my hole position is actually true and it's pretty stinkin good it's it's we are well within 0.01 millimeter hole location in the XY plane which is pretty really good take note that I'm indicating very very close down to the part on the on the drill shank here because if I move up higher the flexibility in the drill shank would interfere of the measurement and also the minimum satisfied plane hole would be result in a way larger measuring error and down here I basically only measure I get about 0.01 millimeters play between the grille and the hole so yeah that's all all pretty good here so now that I confirmed that my orientation is good that my Center is good and my hole location is good I just I used the milling machine just as a coordinate measuring machine basically it's way coarse than a CMM but you get the idea that's nuts the that's basically the workflow you would do on a universal measuring machine like a more okay again pre-drilling all the all the end points of the features we're going to machine this time - flute car bottom floor flute carbide no.2 millimeters and we're running it at 3000 rpm 3200 that is now this tiny fin that we left here needs to be reduced in diameter so there exist going down move table over and swing the rotary table it's a raid radius 16 millimeters so we need to offset by 16 plus half the diameter of the anvil 17 millimeters or climb milling so going down locking the quill and we're going to feed this direction in hindsight I should have made a template to cut the contour from this side too but for this first prototype of this part I guess it's okay to machine it manually okay now we just need to cut this little ear here off a position two rotary table correct picked up the hole in corner just with Dan mill this is just a clearance cut that's a very delicate portion here and we need to clean up this little thing here but I will blend that by hand okay last machining operations are two holes one millimeter diameter very liked press fit for a one millimeter dowel pin and while I have a 1 h7 machine reamer in this case I will would prefer to drill to drill it completely and finish it by drilling because the reamer has about three or four tenth of of ledin so the hole will not be to size all the way down except for the drill tip of course with the drill it will be down to size all the way until it reaches the tip of the drill and what I like to use for such small holes that need a relatively precise diameter our PCB drills these are solid carbide carbide Chang carbide drill piece bit drills with a most of them have a 1 1/8 inch shank or a 3 millimeter shank and this drill surprisingly accurate if you go with one of these into soft material it will be a few microns under sized usually from nominal that's why I have a whole bunch of them have them ranging from 0.03 millimeters up to I think this is 6 millimeter one with a reduced shank I didn't buy this I didn't I got this in a a bunch of tooling usually I use them up to 2 millimeters they've worked brilliant and soft materials like aluminum and brass and if you're very careful because they were ground to a very fragile geometry if you're careful you can use them in and steel tool steel also they were super fragile of course because there are saw the carbide and in this case we were going just drilling aluminium because I want a definite a good location and a good diameter tolerance I will free drill point nine millimeters and then I open it up with a one millimeter drill to size and I already did a test piece this gives me a perfect press fit you can you can push the Dahle pin in with the end of a pair of tweezers and it's in there no play perfect so yeah get some piece of betrayal Sarah there are surprisingly cheap one of these goes for about three three three euros something like that depending where get them okay there we go that's the point nine millimeter drill I already spotted the position of the hole and I'm using a drop of alcohol to lubricate the cut there we go 2.9 2.5 millimeter deep now we change the next hole precision there we go now we change to a 1 millimeter drill okay there we go now we have our large 1 millimeter drill in there that stop is set as he saw it only machined a tiny whisper of material out there and a one minute out and will be a tight fit in there okay here's part here are the dowel pins that will go in there they are one millimeter in diameter five millimeter long stainless steel hardened I had to order them from me sue me because no one else no one else had them in stock for a reasonable price and in small quantities alright what I don't see off done when you when you are about to press a dowel pin into a part a delicate part and an expensive part I check the dowel pin before you hammer it in take a magnifier take it under a microscope look at it check if it was used before if it has calling fretting dings I rolled over edged something like that just check it look at it that's it's in perfect condition and then you use it otherwise you will mess up the bore you hammer it in or press it in yeah I don't I see I see a lot of people just take one random doll pin and Hammer it into an expensive part and scratching the bores and almost broaching them out if the the dowel pin has a purse oh yeah look at them this part is almost done needs a little bit of hand blending in here and in here and then it will go into the wider for a tumbler I will show you that too because that's a new machine okay I'm using Emery cloth and needle files just to clean up the last features of this part before they go into tumbler this is just 400 grit Emery cloth wrapped around a needle file and that's very useful to work certain areas of a part and compared to a file you can go sideways and is it just for cleanup I'm not changing the geometry of the part in any major way I'm just removing some of the tool marks before it goes into a tumbler and this is very much how the mold makers at work do they're polishing they'll use a lot of stones or a lot of needle files and a lot of Emery cloth but with increasing better technology especially wire and Ramy dm+ hard milling polishing and hand blending has gone back a good amount we'll chamfer this internal corner here very slightly with a scraper a tiny tiny tiny chamfer back here - it's almost like whittling and be the tumbler of will ease all those corners very lightly okay these are the two parts this job consists it's this tool here out of aluminium and this one with the internal square and I broached on the life using the rotary broach the stainless has relations cut all the way around to film this one both of these will now go into the tumbler that's about it for a tumbler this is basically a large container in this case it's out of rubber this will last a long time mounted on a shock absorbing mount and there's a motor hanging off the bottom with an ass on off center mass and this will why bring this whole tub and agitate all media that's inside this container media in my case are these triangle or pyramid shaped stones this is this is a some kind of plastic with abrasive in it very mild abrasive and I have a bunch of them I do not leave my media in the tumbler i I take it out I wash it then I store it dry kind of dry yeah that's the media you can run it dry but then these stones are relatively aggressive and it's very loud too you have to make sure that not that holds the container to the to the motor mount is so relatively tight otherwise it will get very loud over time because everything rattles itself lose alternate answer you can see the the the motion of the media that's going to happen I add usually about 30 milliliters of water to between thirty and sixty one or two of these tiny cups and a very small amount of dish soap the water dampens the whole effect of the abrasive media and the soap depend prevents the aluminium from getting cloudy and if you leave the soap out it gets weird yeah place the parts in here we have a cover rubber water large fender washer and a knot tighten everything down cutting it down very far otherwise the cover will come loose and make a horrendous noise and that's the type of the tumbler I'm using its spirit waa - 3.5 serpent v is the volume of the container in litres and has a ginormous 0.05 one kilowatt motor okay there we go now we can fish out the parts they were in for about one and a half hours now and they should have a nice finish and a nice corner rounding there is one of the parts I don't like to dig in the stones I just turn it on for a few seconds and wait until the part rises to the top if you have a lot of small parts in you have to dig dig the stones out and and put them through a screen there you go of course as usual a stone is stuck in the bore that's very common next we will use some ceramic polishing media one build me two round balls three years but this is already looking very promising now we get all the stones out we wash them in a stream and we do not let the water with their brace if an the plastic particles from these stones get into the drain we have already enough plastic in our water okay here we are off the tumbling as you can see very very nice very even finish now except for the internal corner here the stones cannot reach in there also in this pocket but I finish this already with some scotch brite all the corners are very lightly broken and rounded over and this is nice just a fabulous finish same for the stainless part here very nice even here at this large countersink we have a nice blend into the flat surface here very happy with that that's that look it looks instantly like it's a million bucks worth next I will drop it into the ceramic media for for a even finer finish okay one part missing is a m1 screw with a tiny tiny snap ring groove I ground a point three millimeter parting or grooving tool out of carbide on the d-pad grinder this is point three millimeter across the width and frontier and I have a m1 stainless screw here which goes in a 5c collet and now we will set the stick out you need about a little bit over three millimeters of stick on enough to chuck clamp it tightly we do not want to crush the threads now we will touch off with the with the parting tool on the left side of the screw head this works well with magnification I did the first one just for testing with a magnifier now I'm using the camera with a macro lens and I'm just looking at the viewfinder okay that's close throughout the Dro step-over 2.1 millimeters that's the dementia specified in the drawing and take a cut we don't need incredible high speed for this operation just running at about 500 rpm [Music] there we go that's all that's needed with hardened dowel pins they have a chamfered side and they have a site that's rounded over generally the side with the champ or chamfer goes into the bore first to prevent damage to bore but it's up to tourists you still if you're not super super careful you still can damage the bore because the intersection between the chamfer and centerless ground pin is still an edge so soft materials like aluminium it's a good idea to take a stone and just round over this edge for example on the leaf doesn't meet much dokgo abort danke crazy use a fine stone I like a fine Ruby stone a tegu seat stone or use very fine aluminum oxide stone or use some 3m lapping film over a piece of ground stock or a parallel or something like that and you will get very good results I oppressed in the 1 millimeter dowel pins that's very unspectacular just down on the milling machine using the quill and I mounted the m1 screw with the snap ring the e-type snap ring this is just so the screws captive in there it doesn't fall out when you handle this part so yeah those both both parts are done I rinsed them in isopropyl alcohol blew them after they were free of dust carved up a block of PE foam I think it's PE foam or polyurethane foam I'm not sure very rigid packing foam multi-layer type so the parts do not get damaged during shipping there we go we'll wrap it up in Tritton foil package it and send it out hope you enjoyed these a little bit unusual parts sorry I cannot tell you what those are for there there are a piece of air a piece of equipment so there we go so but I was thinking that there are still a few interesting machining operations in those two parts at least than the one i showed you so thank you all for watching and see you next time you

Channel: Stefan Gotteswinter

Views: 75,473

Rating: 4.9646463 out of 5

Keywords: optimum mb4, machining, opti mb4, rotary table, rundtisch, teilkopf, dividing head, deckel G1L, isel, cnc router, mechatron, pantograph, stefan Gotteswinter, zerspanung

Id: spMN4oqJiNQ

Length: 47min 28sec (2848 seconds)

Published: Thu Jan 24 2019