Digital Readout! DRO! How to buy, install, and use 'em!

if you take away only one thing from this video make it this hello internet my name is quinton and this is blondie hacks today i'm going to talk about digital readouts or dros people are always asking me how do you set one of those up how do you use them are they worthwhile for hobbyists let's find out you've no doubt seen these hanging off the back and sides of the machine tools of the cool kids and they're not just there to make it look high-tech in that 1980s sort of way there's two main components to the dro the control unit here and some number of scales mounted on the machine ideally you'll have a scale on each slide so for a mill that's going to be three or four if you include the quill and for a lathe that's typically going to be 2 the cross slide and the main carriage but you may have fewer than that for example on a mill the x and y are by far the most useful scales so especially on older dros you may have only those two and then there will be a mess of cabling that connects each of the scales to the control unit now when you see them on the machine they just look like a featureless aluminum bar but this is actually just a chip cover so under here you can see the business end of it getting low down here we can see how it actually works on the moving section of the slide we have this aluminum channel here and up inside this channel is a scale nowadays it's going to typically be a glass scale that has a photographically printed pattern on it that's read by an optical sensor in the old days this might have been a magnetic scale and then on the stationary part of the slide you've got a head here which reads the scale so this is where the optical sensor or magnetic read head is going to be so you can see as i move the table that the scale moves with the table but the sensor remains stationary and then you can see the cable coming off the sensor that goes up to the computer if you're looking to buy one of these and you can get them direct from china very cheaply on ebay there's really just two things to look out for first all of the buttons on the front make sure that it's going to have all the features that you want and you can tell by examining grainy photos on ebay if they're all here and then the scales themselves and this is really where the differentiation is in the different kits the kits will have different lengths of scales different quantities of scales and different resolutions of scales length and quantity are obvious make sure you have enough of them and that they're going to be long enough to cover the travel of your slides so that just leaves resolution and here there are two types 1 micron and 5 micron any modern import dro the scales themselves are always going to be metric if you're on a machine and wondering what the resolution of the scales is just put it in metric and look at the last digit and then move the table the smallest amount that you can and you'll see that this machine has five micron scales in it because well they're going up by fives typically the one micron scales are only a little bit more money and if it's in your budget i do think they're worth it especially if you're going to be using the machine in imperial and the reason is that as i said the scales and also the software are all operating in metric so when you're running in inches it's just converting those values for the display it's putting on a show and of course microns are never going to convert evenly into inches this digit here is whole inches and this digit here is your thousandths and then this is your tenths and this is hundred thousandths or ten millionths as they're sometimes called this last digit in particular is going to be pretty fictional because this is where all of the rounding is going to happen when it's converting from microns into inches maybe sometimes this digit as well if you're into the ones and nines here then this digit can be a little suspect as well but this last digit especially you really gotta take it with a grain of salt in imperial but this is true of metric as well because this is a five micron resolution so anywhere between zero and five microns this last digit might read 0 or 5. but in imperial you have the additional unknowns of rounding and you don't know how many significant digits they're using in the fpu for this conversion or who knows maybe they're even doing it in fixed point you don't know anything about the software doing this conversion so i treat this last digit kind of like a cat it looks nice and seems useful but you'd never really know what it's going to do if your machine didn't come with a dro and you're trying to install it then what you need to do is find a convenient place on the split line of each of your slides to mount the scales and the sensor so in the mill this is usually pretty easy just find a flat spot on the back of the table and then you know mount the sensor down underneath there the key here though is that the scale needs to run just as true relative to the sensor as the table runs relative to the base of the mill now some mills may have curved castings on the back or otherwise make it difficult to achieve that but you can compensate for that sort of thing by for example mounting the scales on studs that have nuts on either side that let you shift the scale this way and you can use slotted or oversized holes to shift the scale this way as needed and then run an indicator down the top of your scale and make sure that it runs just as true as the actual table does and then same thing for the sensor if you can't make it perfect make it adjustable so mount this on some sort of studs or something that will allow you to shift it around a little bit and adjust the angle as needed so that it runs cleanly within that slot all the way down the length now when choosing your mounting location obviously you want to choose somewhere that's easy to mount it to however check that it's not going to be in the way for example on this mill it's mounted on the back of the table which was convenient because it's not going to be interfering with any controls here however being on the back it does cost about an inch of y travel because the table is going to hit the column sooner than it would if the dro wasn't there in this case there was no choice there wasn't anywhere to put it on the front but consider that depending where you put it it may cost you travel and i'm not gonna lie there have been times when that inch has caused me to express some adult language the table slides are pretty straightforward but the zed slide can be a little trickier now on a column mill it's pretty easy there's usually a big column to mount it on on something like a bridge port an email however you might be dealing with curved castings and you know there might not be an obvious place to put it those machines pre-date dros quite a bit so they were designed without mounting one in mind but once you've chosen your locations and your mounting hardware then it's just a case of drilling and tapping into the castings and if you're worried about drilling holes in this big beautiful whales index or cincinnati mill that you just bought you can always patch them with jb weld if you do it wrong touch up the paint or the holes are likely to be under the dro anyway and hey i won't tell anyone if you don't the lathe is usually easier you've generally got plenty of room on the back of the ways for the main carriage slide and then just pick whichever side of the cross slide is going to be easier or less in the way okay let's learn how to use this thing one of the interesting side effects of chinese electronics markets is that they have created de facto standards for user interfaces in electronics so you can go and buy 10 different bluetooth speakers and they'll all have the exact same controls and this is why and so it goes with dros as far as i can tell there's two different board sets for these coming out of shenzhen one of them says abs here and one of them says ale when it's in the absolute mode so that kind of tells you which one you have so those two board makers are selling those boards to control unit makers and a bunch of those control unit makers are reselling them to other companies that are branding them and packaging them up with scales and selling them on but that's good news for us because i can show you how to use this one and it's likely very close to how yours works if you're new to machining a reasonable question would be what is the dro actually buying you sure it shows you motion of the table but so do the hand wheels so what's the big deal the big deal is that the scales are mounted directly on the slides they're measuring motion of the table directly the hand wheels while they have markings on them they're inferring motion of the table from rotations of the lead screw so what that's doing is introducing an additional layer of mechanical abstraction between the measurement and the thing you're measuring all mechanical systems have backlash in them there's a lead screw and a nut down there and you're measuring the backlash of that system in addition to table travel so i can turn this hand wheel to there and now i can feel it has engaged that lead screw nut in the other direction and now i'm measuring table travel and if i go back the other way nothing only now am i measuring table travel in the other direction so every time you change direction with the hand wheel you have to account for that backlash now look at what the dro does you can hear from the power feed gears in the background there that i'm wiggling the hand wheels back and forth the dro is not moving because the dro knows that the table is not moving despite wiggling around within that backlash area so this is the big win for the dro it basically gives you hand wheels with zero backlash so as i take up the backlash the numbers aren't changing until i engage the lead screw now the table's moving now the numbers move but don't be fooled by the computeriness it's still measuring relative motion just like the hand wheels not absolute position that's actually a good thing though because what that means is we can use the zeroing to set an origin or a reference point anywhere that we want so you can set up a part with an edge finder or whatever zero out your axes and now you can always get back to this spot so this is equivalent to zeroing your hand wheels but much more precise and much more useful because this is independent of direction of travel unlike the zero on a hand wheel which depends on you having taken up the backlash before you get to it so one of the most common things you'll do with the dro is use a tool like an edge finder or a dowel or an indicator or other methods to find a specific feature on your part that you want to reference from and once you've got that all set up physically on the table now you can zero that out and from here you can move around your part with reckless abandon putting features relative to this origin however you need to and you can trust that they will always end up in the right place because there's no backlash and this is very precise but wait there's more there's actually two coordinate systems if you take away only one thing from this video make it this the absolute and incremental button switch that and now you're in incremental mode and now you have a completely separate second coordinate system for all of your axes this is incredibly useful because usually your absolute zero is something that you want to preserve for the length of your setup once you've got that part set up you're going to want to move around it doing various operations on that part and you never want to lose that absolute zero however when you're forming a specific feature on that part you'll use the absolute to get to where that feature starts but then let's say you're cutting a slot that slot is going to have a certain width and you need to do multiple passes you want to keep track of how you're doing along that feature and you can do this with the absolute scale you just have to do a bunch of math and that's error prone or you can just switch over to incremental zero this out at the start of your feature and now this allows you to track your progress on that feature that's just one example of how incremental is used but it's incredibly useful to just be able to jump over here anytime set a new zero do some stuff go back to absolute and know that you haven't lost your true origin on your part now let's look at some of these more exciting looking buttons on here and there are a lot of them and there's a simple reason for that once you have reliable tracking and you've got a microcontroller in the loop then all of this other stuff becomes really easy so you might as well do it the simplest and most used at least for me is probably the half function and what this does is takes the value of any of your scales and just cuts it in half and that might seem of dubious value why would you ever need to do that but what it allows you to do is find the center line of things let's say i want to find the center line of my part along the y-axis so i use my edge finder i find one edge of my part and then i zero that and then i find the other edge then i select my y axis and i have it and there's half of the y value okay well great poindexter obviously but what good is that well the superpower is if i now go back to zero or as close to zero as we can get with that imperial conversion that we talked about but this is now the center line of the part so this zero line is right between those other two readings on the center of the part because we went from zero then to the other side and took half of that and now we're in the center it's a simple trick but surprisingly powerful and it's something that you do really really often because the center line of a part is very often a reference for all the features on that part since most mechanical parts are symmetrical on one or more axes second most powerful function is bolt circles or maybe that's for navigation or maybe when frozen it moves the island but both circles are quite challenging to do without a dro traditional methods for making bolt circles vary but they generally involve first locating all the holes you can do that based on the cord of the circle or various other algorithms and formulas that you can look up in the big book and then you have to either lay out those holes or locate them all using hand wheels and very careful management of backlash but of course the bolt holes are in a circle hence the name so as you pass through each quadrant you're changing direction in either x or y and as we've learned earlier anytime you change direction managing backlash becomes quite challenging so doing both circles with traditional methods can be quite challenging and to do very well can require a lot more skill than frankly i have but there are other methods as well for example you can use a rotary table or dividing head but this hundred dollar piece of chinese electronics replaces both skill and entire expensive fixturing tools we can just push a couple of buttons we can rotate a bolt circle of any number of bolts position it anywhere we want on our part and it guides us to each hole bob's your uncle so easy even a hobbyist can do it let's do a sample six hole pattern here on a half inch radius so you're going to start by positioning the center of the circle on your part so i'll move my table over to wherever the drawing says the center of my pattern should be and let's put it at 300 negative 300 and press the bolt circle button and the first question it's going to ask is for the coordinate plane that you want and normally that's going to be x y the plane that your bolt circle is going to be in but there are other options for example if their head on your mill was rotated you could do a bolt circle in the yz plane on the end of your part but i'm happy with x y so i'm going to push enter and now it's asking us for the center position of our circle and this is relative to where we are right now so typically zero is going to be what you want next question is diameter now we wanted a half inch radius so i'm going to put in a one inch bolt circle diameter then we press up arrow to go to the next question and now it's asking for starting angle and this establishes the rotation of our bolt pattern zero will put hole number one on positive x but you can rotate the entire bolt pattern by using a different starting angle and align your holes different ways on your xy plane some common use cases for start angle would be if you're doing let's say a six hole pattern you can choose whether the diamond of the hexagon is pointing up or sideways or if you're doing a four hole pattern you can choose between having a diamond or a square pattern but i'm lazy so we're gonna do zero as our starting angle next question is ending angle and this one is interesting what it means is the bolt pattern does not have to be a full circle you can have your six hole pattern be on the arc of a circle if you want or as is more common you're probably going to want to make it an entire circle so this is a common source of error if your bolt pattern comes out all squished looking this number here is probably why so start angle was the angle of hole number one and this is the angle of whole number in this case six so generally what you want to do to get a complete circle is take 360 and subtract the angle between two of your holes so in this case we're going to go 360 minus 60 for six holes and we're going to end up with 300 as our ending angle so i'm going to put in 300 and that's going to give us a full six hole pattern on a circle up arrow one more time and last question i promise now it wants the number of holes in the circle so of course that's going to be 6. and here's the magic it's telling us from where we are now how to get to whole number one we just got to set these values to zero it's telling us that we're already set on y so we just got to zero out the x and y zero well what the dro is doing is moving the origin to each hole so that's why we always move it to zero now we can drill or chamfer or whatever our feature is that we're making on this pass on that location and then press up arrow again and there's hole number two and it's telling us how to get to that hole now we're making a hexagon here with the points horizontal so you can see how these numbers here are going to take us up and to the left of the first hole which was on positive x and then we're going to drill hole number two now what's cool about this is you can go back and forth between your holes with these arrows as much as you want so for example if you want to reduce your tool changing time you might want to spot drill all six holes and then pilot drill all six holes and then drill and then ream and then chamfer all six holes rather than changing tools 36 times or whatever it would be just cycle through all the holes with the first tool and then when you get to the end it's going to say game over man and then you can just hit up arrow again go back to hole number one and do another lap with the next tool and once you're done done just push this button again and try to figure out where the island went so i'm a big fan of the bolt circle function now the next most useful feature is very similar and that's the linear drilling function it works very similarly to bolt circles but it allows you to make a series of features along a line on your part in any orientation which is something you do pretty often so this feature will feel very familiar by now you just engage the mode and again the first question is what plane is your line going to be in it starts with x y which is obviously the most common but you know you could do a line in xz or yz if you were so inclined but we'll go with x y here of course now we need to describe the line segment that our holes are going to be on and we have two options for doing that here the first way specifies the total length of the line plus the angle where zero is positive x this method is the l len mode line length mode or you can go to the l step mode and specify the distance between each feature along with the angle as before which one you use might be down to whichever makes more sense for you in your head or might be based on the information you have in your drawing so i'll use l step mode and let's say we want to drill six holes that are each a half inch apart so i'm going to hit enter on l step and now it's asking us for the step size the distance between each hole so we want half an inch i'll put that in hit enter there and up arrow for the next question and now it wants the angle off of zero and that's positive x now i keep saying that positive x is zero for all of these angles but you're going to want to do a dry run and just double check that that's the case usually it's going to be positive x and then the angle is going to be counterclockwise from positive x being your zero but you want to double check that and other planes of course may be different but for this exercise we'll do a 30 degree line so i'll just punch in 30 and enter next question now it's asking for the number of holes we decided we want six so we'll enter that and now once again it's telling us how to get to the first hole now this feature does not let you move the origin of the line the way that the bolt circle feature does so the first hole is always going to say zero and it's assuming that you were there when you started this mode but you'll make your first hole hit up arrow and now it's telling us how to get to the next position which will be half an inch away on a 30 degree slope and now make hole number two and then up arrow do number three and so on and just like the bolt circle function you can go up and down through your holes iterate as much as you want and then when you're all done you get to six you're going to go up and it's going to tell you you're all done but you can still go back to one or do another lap with another tool or whatever is easiest for this operation and then once you're done line dancing just push that button again to get yourself out of that honky tonk so that right there is going to cover 99 of the things that any hobbyist is ever going to need to know about using a dro when you're ready to push your dro skills to the next level brush up on your engrish and tunnel your way into the nion impenetrable manuals that come with these things the next thing you might want to look into is the sdm function or set datum remember how we talked about absolute and incremental give you two different coordinate systems well the sdm feature gives you like another 100 coordinate systems you can use this guy to set data all over your part anywhere that you might need to keep track of things english sidebar you don't really encounter the word datum a lot outside of machining nerd circles but it's the singular form of data so there you go now you can impress your friends with that little factoid at parties well once we can have parties again another advanced thing you might look into are the tool offsets if you're using let's say five different tools for an operation you can tell it what the offset of each of those tools is and then call up those tools as you use them the dro can automatically adjust your position shown on the display for let's say the z value of the end of each end mill now for that to be useful you have to have repeatable tool holding which in a mill in a hobby shop you probably aren't going to have if you're putting your end mills in collets of course that's not repeatable in zed those end mills are going to be in different places each time but if you were going to do like a little production run it might be worth investing in end mill holders that are repeatable in zed and you could set them all up ahead of time and use your tool offsets and that's my crash course on the dro for beginners i hope you see how powerful this tool is for what it costs and will consider one for your machine tools thank you very much for watching please consider supporting me on patreon if you like what i'm doing here and we'll see you next time you

Channel: Blondihacks

Views: 90,227

Rating: 4.9688573 out of 5

Keywords: blondihacks, machining, machinist, abom79, this old tony, vintage machinery, steam, electronics, making, maker, hacking, hacker, lathe, mill, woodworking, workshop, shop, model engineering, engineer, engineering, live steam, machine shop, metal lathe, vertical mill, metalworking, metal shop, jewlery making, diy, home improvement, resin casting, how to, do it yourself, do it yourself (hobby), ASMR, mini mill, mini lathe, tutorial, digital readout, DRO, DRO for milling machine, digital readout DRO

Id: DZz8KlzJcEA

Length: 22min 26sec (1346 seconds)

Published: Sat Aug 29 2020