Afraid of Micro Machining? An Introduction

if you are afraid of micro machining in other words using end mills smaller in diameter than 1 8 of an inch or three millimeters this episode is for you welcome to another episode [Music] most of my experience working with cnc machines is actually using end mills of 1 8 of an inch or 3 millimeters roughly in diameter or smaller this is a look inside my partially organized drawer and the thing that you can see is that i have some 3 8 inch end mills but fairly quickly they get smaller and smaller so this row is already 1 8 of an inch diameter for the most part and then we get to 1 16 1 32 of an inch and then we get down even smaller like 15 thousandths of an inch in diameter and 10 000 inch in diameter all of these are end mills that uh i used on my tag before i got my haws and the point of uh making that comment is to explain that you know something like a 10 000 diameter end mill this is a ball nose end mill you can use on a machine that's not very rigid you just have to be very conservative about your feeds and speeds and depth of cut and width of cut here's a look at what i have loaded into my tool changer at the moment these these are it's a 20 tool two tool changer which is mostly full there's one spot missing because i broke an end mill but you'll notice that except for a few large cutters the ones in the back are all micro machining or micro end mills this one for example is my um 1 32 inch diameter super long reach end mill which is 15 millimeters length a reach and uh it's funny i mentioned this before that they mentioned the diameter in imperial but the reach is in metric that's how they measure it though i started with a roland mdx 15 or 20 i don't even remember which which had a maximum shank size i believe a 1 8 of an inch and then i moved up to a tag desktop machine but most of the work that i did was for injection molds for small detailed parts and so i needed to use smaller end mills which means i was uh rarely using them nose larger than one that ate them an inch in the early days i did it by trial and error and that meant that i broke a lot of end mills so eventually i kind of figured out okay here are some feeds and speeds that work for these different end mills and i stuck with that that's not how i do things anymore and the difference between the way that i used to do it and the way that i do it now is that with my current approach i can work with standard reach end mills which are three times the diameter for the reach all the way up to super long reach end mills like uh 1 32 inch diameter with 15 millimeter stick out which is over 10x what i'm going to do is show you the process that i use working with these end mills and for the most part i don't break end mills anymore uh even the really tiny ones when i do break an end mill it's because i have done something with the cam that causes the load on the end mill or the side force to be too high such as i'm taking more of a depth of cut or more of a width of cut than i calculated the feeds and speeds for so let's head to the computer and i'll show you how i calculate the feeds and speeds i personally use g wizard for all my feeds and speed calculations other applications like hsm advisor i don't have experience with those so i'm going to focus on g wizard and show you how i use it and i imagine most of these things will apply to other speeds and feeds calculators so i'm going to first show you how to do this with a tool kind of the hard way and then i'm going to show you the easier way to do it so let's start out with a for example a 20 000 inch diameter end melt and the thing that you'll notice is first it says you need 30 000 rpm now i mentioned that i use this successfully with my tag i'm currently using it with the haas om2 that has a 30 000 rpm spindle but i'm going to show you the the difference between them the other thing is i'm not sure why the surface feet per minute is so slow um but we'll come back to that oh i see why this is currently set to a drill so what we want to do is switch to an end mill and i'll do a normal end mill and i'll just leave everything the way it is right now and that's going to show you a few things in particular i have the stick out at one inch which is awfully long for 20 000 diameter end mill i'm going to keep the width of cut to be basically full slot in width and i'm going to set the depth of cut to ten thousandths or let me do less than that yes which is 50 percent of the diameter there are a couple of things you're going to see right away one is as i mentioned it maxes out the rpm but the other thing which is something really important is the deflection the deflection is the thing in my experience that's tends to break the end mouse now another thing that's important is this aggressiveness scale what i've discovered is that you're the less rigid the machine the farther to the left you want this so for a take for example that has a 10 000 rpm spindle i might set it like this now the stick out i mentioned is way too long let's set this so that it's a standard reach and mill which means the reach would be three times the diameter so in other words 0.06 so if we change this to 0.06 you can see that it's okay with the rpm now and the deflection is okay so if we want to get the deflection down to give us a better safety margin we might want to reduce the depth of cut to five thousandths of an inch so this is what i use to calculate the speeds and feeds so this is telling me that i need to run at 10 000 rpm it suggests now use conventional milling rather than climb milling my guess is that's to reduce the deflection uh even further because with climb it could catch and try to pull it into the work and therefore snap the end mill and then the feed rate is pretty low switching this to 30 000 rpm you know watch what happens to the feed rate you can see that it goes up quite a bit which is what you would expect filling in this information and setting everything up for each tool as i go through and do the cam is pretty painful one of the things that's nice about g wizard is it has this tool grip what i've done here is to create the different tools that i'm using fairly often so you can see here's the 132nd inch super long reach end mill and what that means if we go back to feeds and speeds i can use the default crib and then i can set select that uh super longreach end mill which is right here and now that's filled everything in so i've got the stick out i've got the the number of flutes the tool diameter etc and this is showing that i can use the 5000 steps of cut with the 20 000 width if i do slotting you can see the deflection becomes too high so that means i need to do reduce this even further and you know i think using a depth of cut of you know either one or two thousands of an inch is what i ended up doing i think i used one thousandths of an inch for the depth of cut when i actually use this so obviously you don't want to use these super long reach tools for everything what you want to do is work your way down let me actually bring up the case where i use this tool and show you how i actually used it along with other tools here's one of the parts where i use the super long reach end mill which is this one right here actually that's a ball in mill this one right here so it's the super long reach as you can see flat end mill and i used it down there but of course i needed to remove material from this area before i got there so let's take a look at the just briefly the steps for getting there so the first one is we're using a 3 16 inch flat end mill to get rid of a lot of the material and then we're coming back with a 1 16 inch flat long reach end mill and that's getting more of the area if i were to redo the programming now i would change how i did this so don't take this approach as the important approach the thing the thing to notice is that it's removing more and more of the material there if we look at this operation you can see that it has a stock to leave of 10 000 roughly radial but zero in the axle so that means when we come down to let me go down a little bit further so when we come down here we're doing a scallop but it's not completely cleaning that up along the wall here so this is where what i wanted to do is use this horizontal and you can see it cleans up that wall there and so if we look at the the scallop you know it has a ball end mill so the ball means and there's no stock to leave the ball means that there is a little bit of material and so that means that when we run the 132nd inch long reach end mill we're not using too much material now if we take a look at the speeds and feeds you'll notice that we're running at about 10 inches per minute and if we go back to g wizard we're using the same super long reach end mill and this is pretty close to the 12 inches per minute this is for slotting whereas here i'm actually moving over by less than the full slot with but i was being conservative and i did several different molds with the same end mill and did not break the end mill so i know it works here's another element that definitely requires micro machining which is the logo here the mod mount logo and let's take a look at it the first thing is if we take a look at the depth here you'll see that it's 10 000 of an inch in some cases the depth was smaller in some cases for example it was only a couple thousands of an inch but the more important thing is the width right here you can see that it's just 21 thousandths of an inch so that means in order to mill something even approximating the shape i need to use an end mill that is no larger than 20 thousandths of an inch what i'm actually using for an end mill is something which is oops wrong one something which is pretty cool i'll bring up that tool and what i often do is i sort by diameter so the first thing that comes up is the tool that i'm using this is a 60 degree engraver so you can see it has this shape here and the very end of the tip is just five thousandths of an inch in diameter if we simulate that uh this is going to take a little bit so first i'll show you the tool path before we simulate it the tool path is right here which is a pocket tool path and you can see it's doing several depths of cut and it's actually because the tip is so fine it's giving us the shape that looks fairly close to what we want i'm not doing a full simulation because that takes a long time but this gives you an idea of what it looks like here's that same part this is actually one that i made a mistake on and had to email but you can see this is the logo i can barely feel it i think we changed this one so that i was only a couple thousands of an inch deep uh but you can see the the detail turned out really well here is also another piece not the same one uh with the logo on it and this time you can actually read it and again it's it's uh very very shallow you know but it looks really really good and i was able to do that with that small 60 degree 5 000th diameter tip end mill and i've used that 5 000 inch diameter engraving end mill quite a bit and have had no problems in the previous video you can see an example where i ended up accidentally milling something that wasn't supposed to be milled that way so the angled sides on here were milled by the sides of the engraver which was not the intent and ruined this part but the tip is fine it was not broken by that that's one nice thing about using a 60 degree engraver which is the tip is going to be a lot stronger than if you actually used a 5 000 diameter conventional you know standard reach end mill or even a stubby one i also have a three thousands uh dye inch diameter tip that i haven't tried yet but the 5000 stamina tip has worked really really well that's a little bit of an introduction to micro machine if you have questions that i haven't answered please comment below and i'll see if i can answer them either in the comments or in a future video i hope you enjoyed this episode please subscribe give me a thumbs up comment below and i'll see you next time [Music] you

Channel: JohnSL - Random Products

Views: 39,790

Keywords: CNC, Micro Machining, Machining, Mill, Fusion 360, gwizard, end mill, feeds and speeds, milling, machining parts, micromachining process, micro machining cnc, end milling, feeds and speeds manual, feeds and speeds for aluminum, feeds and speeds for stainless steel, feeds and speeds cnc, gwizard vs hsmadvisor

Id: 6HpHvuyJBF4

Length: 14min 36sec (876 seconds)

Published: Sat Jan 02 2021