hi folks welcome to Kern Kernville some of the most high-end most accurate most stable CNC machines in the world Kern is located in garmisch-partenkirchen in southern Germany just on the Austrian border and honestly one of the most beautiful places in the world this was an absolute treat to get to see the inside operations of this facility how they build these machines and what makes a Kern a Kern and when I say accurate we're talking machines that can regularly produce plus or minus 0 micron accuracy or 00 million of an inch it's not just that ability to make one part incredibly accurate it's that ability to tie in there amazing machines that have a huge number of tools tool holders wore holding automation so that your first part has the same tolerances and accuracy and precision and surface finishes as the 000th part so let's walk through some of the coolest tidbits and factoids we learned on this tour number one how did they get started Kern didn't start as a machine tool builder and in fact to this day Kern runs one of the most high-end most precise job shops in the world and certainly within southern Germany and a significant portion of their business to the safe remains operating that job shop and it was that job shop work that led to the creation of their first machine decades ago companies like IBM and Siemens and other folks in the medical and aerospace world had increasingly high demands of the parts they needed done and long story short Kern realized the way to make these parts was to build their own machine to their own spec to their own design and after they built the machine some of those customers said oh well if you're building one we'd like to have one as well in fact you might have recognized the pyramid Nano from the Nicholas Hackl watch tour video that's another industry that current is incredibly well respected and given the absolute intricate tolerances and incredibly small detailed work required in the watch making world but if you haven't heard of current I don't blame you they're an incredibly small company and every year they put out less than 000 machines usually all pre-sold number two let's stop talking about that accuracy and put it to the test the day that John Grimm's will and I spent touring current manufacturing facility as well as their job shop we made a test part and on that test part we did a five axis swarf style operation as well as an interpolated operation of effectively an hsk taper with the interpolated tool path we have the X and the y axes constantly moving and actually changing directions as they move around the four quadrants of the part which really tests the accuracy of the machine particularly as you hit those points where for instance the x axis moves from going positive to going negative with the swarf style operation it's your classical five axis of style tool path where the tool is actually remaining in one location your a or your B axis is tipped up at an angle and then your C axis rotates the part around as the tool cuts we then took that part over to their state-of-the-art calibrated Zeiss CMM to confirm those accuracy numbers and the interpolated accuracy meaning that part was machined while the X and the y axes were in motion was 0.0 microns and again that's across so probably one and a half inch or forty millimeter area with the Zeiss at CMM doing constant contact measuring around that for accuracy circularity tolerance etc number three some of the parts that are made on the Kern are so small they're actually pretty difficult to see or find with the naked eye here we're looking underneath a microscope to try to find the part I could see a speck of something but I wasn't sure that was even the part absolutely amazing here's that same part but 000 times larger number four even though these current machines have this feeling of being incredibly specialized machines with such an emphasis on accuracy they're workhorses they are designed with automation high tool storage and productivity in mind and nothing exemplifies that better than the fact that k0 which is what they call their own job shop is a job shop that runs 00/0 with a focus on productivity not unlike any other job shop and that was probably my favorite thing about the Kern micro the elegance and design and integration of the tool changer the workholding and automation on the right side of the microbe you have these racks each rack itself holds eight tools and you can have multiple racks in the machine with up to a total of over 000 tools so that you can set up the tools offline or you can store pre set racks offline and it's just a very elegant way of handling job setups and tooling the same interface and that same robotic arm can also have a mix of workholding built into it so you can have a row or other automation style built-in so that in a relatively small footprint you can have something like one or two hundred tools as well as 00 00 or 00 work pieces set up for larger work you can also set up a proper third party your standalone automation system on the left side of the machine your assistant 0 r0 is so that you could either be swapping out palletized workholding or raw materials number 0 the emphasis on thermal stability building a high quality accurate consistent machine tool involves a lot of high quality components and alignment and so forth but it's the thermal element that really sets current apart and one of the interesting things is that when we look at their raw mineral casting base there's nothing about it that jumped out at me is being symmetrical at first glance but it is thermally symmetrical meaning as the temperature rises or lower that casting moved in a repeatable and consistent and even manner and that's what kern does they track that they have a team of engineers or PhDs or scientists who are understand what happens to this forty two thousand rpm spindle as it grows because as it warms up that spindle stretches in Z if you will if they know how much that grows that is programmed in to the Heidenheim control they used oversized motors so that as a motor puts off heat they not only know how that heat grows but by using oversized motors they are able to reduce that I believe by the Kubica function so that there is less heat period many of their machines have huge amounts of thermal flushing moving the actual liquid through the machine again to maintain that stability number six it takes a long time to build a current the machine itself may spend up to six weeks being built and assembled and then a equal amount of time going through its trials and workup and verification every single department within Kern has to sign off on that machine and anybody has the right to say they aren't happy with it they're not comfortable with it it needs to get reworked or revisited and in the end every department head will sign off on the machine including our host Simon the CEO of the company number seven they have a bell at the current facility and men times when a customer buys a machine the customer is able to come and ring that Bell when you buy a Kearn it's not a traditional machine tool purchase you're really becoming part of their story and they're becoming part of your story you're joining their sort of family you're getting to know them on a much more intimate level and it really is a two-way relationship it's really cool number seven did I mention small parts here we are under a pretty amazing microscope vision system trying to find the part that had fallen into the end of a very small glass sort of petri dish style container and there it is now I'm not doing a good job of explaining the scale of that part let's move it so that it's next to a one cent coin effectively a penny and if I still haven't impressed you they can drill holes through a human hair to the point where this is actually now a relatively boring and unchallenging and demonstration for them number eight currents like any modern machine tool have automatic tool changes and thus the tool changing arm is able to change out the tools as you get throughout a CNC or cam program no big deal right well unfortunately sometimes you aren't allowed to use the tool changer anybody guess why some of the tools the Kern uses are so small in diameter that the air friction of an automatic tool change operation could break the tool isn't that amazing and that's why current has specialized vision systems used to set those tools up and measure their gauge length number nine machining carbide this is mind-blowing this is a regular end mill we have had some fun playing around doing this with high speed steel which is quite hard at north of 00 Rockwell this is carbide not only have they machined it they've machined it accurately they've machined it with a really good surface finish and that center hole is thread milled or I believe in em 0 or an m0 screw and number 00 bragging rights on surface finishes other reasons to purchase occurring is minimizing downstream post-processing operations when you have a machine of this accurate not only can it hold those tolerances across a large part run or across many months of operation but you can minimize things like lapping or polishing or sanding or other things that may have to occur as a result of tool marks or inadequate surface finishes the finishes that come off these currents are absolutely amazing in our host Marvin his full-time job as a materials scientist is working up recipes and understanding how to achieve these finishes on various types of parts if you rat IMTS or another tradeshow you may have seen the cloud gate sculpture commonly known as the beam in Chicago that was machined on a kern and this is straight off the machine absolutely superb again a big shout out to kern their hospitality was incredible and the pride they take in the machines that they produce and the culture and the process and the fact that they're so unique and that they're building these machines but they're also running their own job shop where they use their own machines it's really a cool perspective so thank you to Simon and Marv it was a wonderful chance to not only be able to tour it but to allow us to film it and share that with you I hope you folks learned something hope you enjoyed take care see you soon
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