How to Convert a Manual Mill to CNC

working with metal has always been a challenge with the dr. D flow shop I can drill holes and cut sheet metal but fabricating custom metal parts might DIY projects has always been out of reach I'm hoping up from in today with the acquisition of my brand new precision Matthews 8 3 3 TV now I'm not a machinist by any stretch of the imagination so this is not going to be tutorial on how to run a mill but I am going to show you how to convert this manual mill into a CNC one about to be through if you've never seen a CNC mill conversion and you might not know that this requires the mill to be completely disassembled now why can't we just replace the handles with stepper motors well there's an inherent issue with the lead screw drive system and found in each axis of the mill this issue is known as backlash now it'd be a good time to mention that if you are new to CNC motion then I strongly recommend watching my previous video on all the parts and theories that go into building a 3d printer I cover topics like backlash that are applicable to many different CNC builds like the one we were working on today he sees the machinist is able to compensate for backlash but this is difficult for a CNC machine to do it is better to give a drive system it has very little if any backlash like a ball screw a ball screw may look like a normal screw but the threads are designed to act like helical raceways for the ball bearings found within this special nut to substitute the eight three three T's lead screws for ball screws we had to take apart each axis [Music] on paper this conversion seems straightforward but when you start to factor in the weight of this mail the need for a hoist it's a little bit more complicated [Music] now that we have the z-axis disassembled we can take a closer look at the linear motion setup of this mill most manual mills including this one use dovetail ways to restrict the motion of the carriage in one dimension the problem with up two ways is that there's a lot of metal on metal contact so lubrication is key one of the reasons that this mill stood out to me compared to its various competitors on the market is because this mill has a one-shot oiler one pump of the lever Wilson oil through the lines lubricating not only the ways but also the screw we need to be careful when installing the ball screw not to snag any of the oil lines the first step in the z-axis conversion is swapping out the old lead screw nut block for the ball screw one the mounting holes for the new nut block do not align with the old holes so we're going to use an adapter this adapter plate is close to aligning to those old holes but it needs to sit a little bit farther down there's some interference from the casting so we're gonna take an angle grinder to the two corners of this plate to create a little bit of extra clearance you've been within the same make and model there is some variability that exists between the castings of these cheaper import mills so whether you fabricate your own plates for your conversion or you purchase a kit be prepared for some material removal to get everything to fit now we need to add the oil lines back on there's an extra oil line to oil the ball screw nice cool at the top of the z-axis we're going to use angular contact bearings and a plate to hold disease through straight at this point we could attach the z-axis motor but that would increase the length of this column and I'm already worried about clearance issues with the hoist so I will install the motor after the column is back on the base next we need to insert the give which is a tapered piece of metal it'll take the play out of the carriage you don't want the give to be too tight because this will result in excessive wear of the dovetail ways you are probably wondering how I got a hold these ball screws that are the perfect length and these machining plates for attaching the screws and motors while it would be possible for me to source these components from online vendors in the local machine shop I decided to purchase a conversion kit from Bruce Nelson over at heavy metal CNC the kit greatly expedited this whole project and the quality of the components is awesome we're about to start the ball screw conversion for the X and y ways before we do that I'm going to quickly talk about one more selling point of this mill over its competitors this mill comes ala box with hand scraped ways if you're not familiar with hand scraping well basically it's the process of creating an ultra flat surface an ultra flat surface means a better fit between two components and in the case of mills it's going to allow for smoother motion on many hand scraped surfaces you'll find these Halfmoon flakes these flakes act as divots were oil pools now instead of having a metal of metal contact you're having a metal on oil [Music] [Music] [Music] [Music] [Music] my fear of clamps issues with the column was justified when we took some measurements and realized that there's just no way for the column to clear the base with my low eight-foot ceilings we had a shortened the chain on the hoist which made this whole lifting procedure a little precarious so please don't copy how we rigged this lift [Music] I'm pretty excited if the mill is put back together but we can't celebrate yet because we need to make sure that the column is square to the table or it's not going to operate as it should the best way to figure out if the column is perpendicular to the table is to throw an indicator into the spindle and then run it up the edge of an engineer's square now if the column is leaning towards the square or leading away from the square the distance on the indicator is going to change now we can correct this leaning by introducing a thin piece of metal underneath the base this is known as shimming the column over about eight inches or 200 millimeters of travel the indicator changed about 7,000 which it changed I know that the column is leaning towards us so we need to place a little bit of shim underneath the front of the base in order to make it lean back and correct this shim comes in all different thicknesses now I could use a little bit of trigonometry to figure out approximately what thickness shim would correct this lean but there's a lot of factors that go into this and it's almost easier just to guess and check so we'll try a couple different thicknesses of shim oh my gosh again it's so high come on Patrick hold on one second my man we sit in the column with 0.3 millimetres but now we have the opposite effect the column is actually leaning back so we're going to meet in the middle and do 8.1 five-millimeter show the next and last calibration that I'm going to do on camera is going to be to tram or adjust the tilt of the spindle in CNC milling we want the spindle to be precisely 90 degrees in respect to the table it's easy to adjust the angle on a bench top mill because many of these models are made to tilt so that you can drill at different angles how do we know when the stock is perpendicular we can check with this indicator setup basically we sweep an indicator between two gauge blocks that have the exact same height now if the headstock is not perpendicular its slanted one way or the other then when the indicator gets to the next block its reading will change we can then loosen the bolts on either side tap the headstock in whichever direction makes sense and then retighten the bolts Reese wheat the indicator and see if we're getting close when I finally reached a tram that I was happy with I kind of had a thousand some an inch difference in height between the gauge blocks which are 13 inches apart we're almost finished with the mechanical portion of this build we just need to reinstall the one-shot oiler as well as the way covers now the way covers are really important in protecting these precision ground surfaces from projectiles that are created during the cutting process next we need to talk about the electrical control system that powers and coordinates the stepper motors which ultimately makes this a CNC machine [Music] while I was waiting for the mill to arrive I assembled all the electrical components because I need to be able to control the motors while tramming the mill I was trying to be as efficient as possible because I was renting the engine hoist by the day and didn't want to return it until I knew that the mill can move accurately in case I had to disassemble it and fix a problem I will bring the electoral cabinet over to my bench and we can talk about the setup I do want to point out that my Mills current configuration is about as simple as it gets I have who will soon have control over three motors three limit switches and two probes for finding my tool and work offsets more capable CNC Mills will be able to adjust the spindle speed automatically swap tools activate coolant pumps and so much more while these features are necessary in a production setting I remember sided which ones are worth the added cost and complexity from my little garage operation I'm gonna run my mill for a couple of months in this bare-bones configuration before making any upgrades I can tell you already just from swapping in and out my indicator setups then a powered drawbar will be coming to this mill in the near future so get subscribed and follow my instagram so that you don't miss any upgrades when building a 3d printer or other low wattage CNC machines it's not a huge deal to have your controller board and wiring exposed however to move the axes on this mill I needed large power-hungry stepper motors as power requirements go up everything gets more dangerous I'm not just talking about the potential for a nasty shock but any kind of interference with the electrical signals could cause the mill to act erratically here is my quick disclaimer I am NOT an electrical engineer so take everything I say with a grain of salt always ask questions when unsure and never work on a circuit that is under power I will upload the wiring diagram for everything in his cabinet to my website and I will update it as I find safer ways to wire everything and/or add new components continuing with the theme of safety in electrical cabinet such as this one is a necessity to keep coolant the breeze and fingers away from the election components to get wires from outside to inside the box you could drill one large hole fit it with a rubber grommet then stuff all the wires through that hole however a better method is to use panel mount connectors panel mounts exist for all types of electrical connections including bail jacks and the popular Ethernet rj45 connection one of my favorite panel mounts are the aviation connectors they may look a little old-school but it is very easy to solder custom wire harnesses to them like I did when I hooked up the stepper motors and motion pendant AC power is supplied to the Box through a 15 amp switch which is housed in a 3d printed part that anchors a switch to the cabinet the switch handles the entire lower the circuit now it is more common to use a contactor at these higher amperages and have the on/off switch control of contactors coil but I had this high current industrial switch laying around inside of the box we have a 72 volt 20 amp unregulated DC power supply the reason I went looking unregulated power supply over a regulated one was mostly because of cost unregulated power supplies can also soak up current feedback such as when a stepper motor is slowing death without faulting in fact unregulated DC power supplies will never fault if you draw too much power their transformer will burn up if you're just learning the ropes I would stay away from the unregulated power supplies I want with 72 volts because my boards could handle it and I'm eventually going to switch to servos which operate in that voltage regime the power supply feeds three beefy stepper drivers the model number of these drivers is DM h 6t t they can supply up to seven amps there step indirection signals for the stepper drivers come from Mesa seven i-76 e we will talk more about why I picked this controller board when I go over why I chose Linux C and C as the software to run this mill but for now let me explain my love and hate relationship with this board I love it because of how feature-rich it is the seven is 76 II can drive up to five motors and receive input such as the one-liner set up there also seems to be an endless number of visual inputs and outputs so controlling coolant pumps and solenoids for compressed air in the future will be no problem the hate part of our relationship with this board stems from a lack of documentation the manual is cryptic to say the least a simple diagram of which pin was which what is her Feist fortunately the linuxcnc forms got me straightened out before I fried the board I'll compile and expand on the resources I found most helpful on my website finally in the cabinet we have a tri power supply which supplies 24 volts the Mesa board and 12 volts to the intake and exhaust fans which are essential for keeping this cabinet cool let's head back over the mill the limit switches have finally arrived and I will install those before talking about the next C&C so we were back over by the mill and I've made a couple of changes but let's focus in on the limit switches I have added inductive proximity sensors that trigger when a metallic surface like the casting of this mill is brought within 4 millimeters this is a contactless process and is an accurate way to home a CNC mill there are two sensors located at the minima of the x and y axes as well as one sensor at the zmax I used my custom 3d printer to fabricate the brackets that hold the sensors these limit switches while not completely necessary will give my mill spacial awareness so that there is no potential for it to run into itself next let's talk about both the computer and software that run this mill the Mesa 79760 controller located in the electrical cabinet is connected by Ethernet to an Intel nook the until nook is running Linux C&C I pick linuxcnc because I liked how the motor control was performed by the CPU and not outsourced to Hardware connected by USB which means no buffering of movements in higher step rates also there's a lot of flexibility with this open source software however tasks that are simple to accomplish and other scene C programs like sending up a pendant proved to be much harder in a Linux CNC but so far the performance of my men has been worth the extended set-up time a couple other additions that I made was a touchscreen monitor as well as a tool probe for measuring the height of my in melts the touchscreen is showing off a new linuxcnc Yui known as pro basic this interface was released at the end of 2019 it's way more professional-looking than the other goodies that exist and all the buttons and macros are very intuitive it seems to be inspired by 12 aux path pilot if you're familiar with that program the last thing I want to talk about before we fire this bad boy up is the spindle motor this is a 2 horsepower three-phase motor that directly drives the spindle by a belt a variable frequency drive that is housed here controls the speed of the motor there is no oil fo gearbox it needs to be maintained and this motor is incredibly quiet even when it is revving up to its max 3200 rpm [Applause] [Applause] the VFD is not currently tied in with the electronics so setting the speed of the spindle is accomplished by manually turning this knob this will be CNC controlled in the near future well I think that pretty much covers everything so let's get on with the machine the first part that I'm gonna make is a 96-well tiller block these are common in biology labs like the one I work in for keeping small volumes of liquid from evaporating these are like the biology version of whisky stoves but instead of whiskey these blocks will keep expensive biological reagents cold this commercial chiller block cost about a hundred dollars that piece of 6061 aluminum that's in the vise cost me about three dollars so it's time to save some money with this mill we're gonna use three separate tools for the cutting process starting with a three-inch face mill to get the surface flat followed by a six point five millimeter drill bit to create the ninety six equally spaced holes and finally a chamfer tool to clean up the edges of the holes as well as the perimeter of the block to get started we need to find the bottom left corner of the stock material because I said that as the origin of the part in fusion 360 the combination of my digital work probe from neutronics with the pro basic interface makes this process trivial after the probing operation is complete the work coordinates of this aluminum block are automatically adjusted in linuxcnc after switching the probe for this beefy three inch end mill with carbide inserts I'm using the old paper trick to determine the height of the tool because this tool has too big of a diameter to work with the touch plate but don't worry we're gonna use a touch plate the future drill and chamfer bits [Music] [Music] [Music] well that was awesome some of these machine marks that were left on this surface indicate that the mills needs to be adjusted a little bit more but I'm happy with this quality for now especially with this inexpensive facing mill that I bought off of Amazon let's move on in the 96 holes that will be drilled with the six point five millimeter spiral drill this time we will use the automatic tool Center after the touchpad registers the drill bit Pro basic can then compensate for the height of the tool in relationship to the aluminum block to make sure that we have the perfect starting height the mill made quick work out of all those holes I will have to review the video but to me it looked like the drill went straight down and didn't Wallander finally we're going to knock down those sharp edges around the holes as well as the perimeter of the block with the chamfer tool [Music] [Applause] [Music] that chamfer takes this part to the next level it's time for the moment of truth does the 96 well plate fit within the 96 well chiller block yes it does I wouldn't use the word easy to describe everything that went into making my first part but I would use the word manageable from start to finish this project took a month's worth of weekends and week nights but I couldn't have done it without calling in favors to a lot of my friends so big thanks to Patrick the other David sorry Hannah and of course Andy for making this CNC mill a reality I have a lot of exciting projects coming up that will take full advantage of this mill so get subscribed and I'll catch you guys in the next video [Music] [Music]

Channel: Dr. D-Flo

Views: 338,227

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Id: qDr81TccvMY

Length: 26min 38sec (1598 seconds)

Published: Mon Mar 02 2020