So I just completed the high-z mod on my lead 1010, and changed all of the wheels on the whole system, due to rigidity issues. Enjoying the new rigidity, I wanted to see what the machine was capable of. I bought the CNC Cookbook feeds and speeds calculator, and chose the "conservative" option, and added my lead 1010 as the machine. "Conservative" in hardwood (Ash) with a 1/4" upcut flat endmill, .125" DOC, 30% stepover came out to 16000 rpms @ 160 ipm feed rate. Nervously, I fired it up, but was pleasantly surprised that the machine seemed to handle it fine, nice finish on the wood, and dimensionally accurate. So I went with that. The first carve at 3 hrs long went fine. The second carve, 2 hours in, my brushes went out on the router11. Carve finished fine after changing the brushes. The third carve, 30 mins in, the router11 died. The brushes were fine, top bearing was fine, but the router was almost completely seized up. There was only maybe a minute of warning in advance that something was up with it. sound changed, then dead. It was not hot to the touch at all when it died. I cannot manually spin it unless I use a wrench on the collet to turn it. Is this common for the Router11's? I'd hate to give up a feed rate the rest of the system in fine with just to keep using one? Leaning towards a water-cooled 1.5kw spindle. Unless someone could convince me something other than the new feedrate killed it? Any thoughts??
Update: the bottom bearing seized up. Obviously not a robust enough unit. I’ll be replacing with a Chinese water-cooled 1.5 kw spindle. Thanks for all the input and “support” from the community!!
this is a community forum. if you wanted support for the Router11 from the store then you should have contacted the store (-: also, many forum members are not in your timezone, I am 8 hours ahead, so the time tag on your first message is 5:16pm my time, I was just going home from work to spend the next 3 hours figuring out where all the money went, then I went to bed. and no, early bearing failures are not common. brushes are expected to wear out, especially on CNC machine because they run for long periods. when you use the same router by hand it tends to run for maybe a minute at a time, a very different usage profile, that is why you get spare brushes with it. MY Makita router has been running fine for years without needing brushes but I don't cut hardwoods, maybe that makes a difference. The bearing failure indicates a factory problem,a dirt problem or an overload problem.
Hi Bill, It is worth checking in the CNC cookbook feeds and speeds what also happens when the machine cuts at full width (as in slotting) as some CAM software may not generate paths that keep the stepover at a consistent 30% all the time: cutting into corners is a very common scenario where the loads can increase. I have a different calculator software and I ran your number through it as a check. The feeds and speeds calculator can also be used to give you an idea of what to expect with a 1.5kW spindle, as for many wood applications with 1/4" and smaller diameter bits, the spindle power is not often the limiting factor for the bulk of the cutting, but there can be 'gotchas' as below. For the 30% stepover case with the router, and assuming the Ash is on the harder side (i.e. worst-case scenario such as a knot), I calculate that the router could be running up to about 110W, and the sideways load on the bit is about 5lbf. If the tool path does generate occasional full-width cuts, then the spindle load increases to 370W and the cutting forces will increase to about 16lbf. The sideways loading forces at both a 30% stepover or even full engagement are not too extreme and should be well within the router bearing capabilities. For a router that has brushes, it will most likely be a 'universal motor' design which means that as the motor speed goes up, the available torque drops and the torque-speed curve is almost a straight line between max torque at zero speed and zero torque at max speed. The motor power is the product of speed x torque, so the maximum possible power output is theoretically at about half-speed, but in practice motor efficiency can bump that around. As your cut was at 16,000 rpm, the electronic speed control on the RoutER11 would push more current through the windings if the bit cut to full width, and therefore provide more power out, and at the 16000 rpm has plenty of 'headroom' left in router power so should not be overloading the machine, preventing the router from bogging-down in the wood. A spindle though (i.e. brushless) runs as a 'constant speed' (actually 'constant max torque') machine where the max output power only occurs at max rpm, and so if you had a comparable 750W spindle that was rated for peak output at 32000rpm, at 16000rpm, you only get about 375W that is useable.... For the scenario here the 'comparable' brushless spindle may have been maxed-out at 98% load for full-width cuts. I suspect the rated speed of a 1.5kW spindle will be 24000rpm so at 16krpm you would have a theoretical 1kw available, but no motor is 100% efficient so the actual output will be less. The problems mostly arise with wider diameter cutters, such as spoilboard surfacing bits, where they cannot be spun too fast to prevent burning, and hitting a thick-spot when surfacing can make the machine load jump rapidly. Routers can be more tolerant of those situations. If you look at a spindle, check if it is rated for milling, as some have bearings which are designed only for drilling applications. That is, the bottom bearing needs to be rated for withstanding radial loads, and not just high axial loads as in drilling operations.
This is a great response. Thank you!! A brief look into the spindle that I'm looking at, is 1.5kw, 24k RPM rated, min 9k RPMs, and has 3-angular contact C7002 bearings. You know considerably more than I do regarding this CNC stuff, but a basic Google search seemed to suggest that C700 bearings handle radial loads pretty well (not sure how much that varies by manufacturer)... Any input?
Yes 3 angular bearings are quite a common configuration and would be fine. There are a few spindles out there specifically for drilling/tapping that have axial (thrust) bearings as the first set, which cannot take the radial loadings seen in milling over prolonged periods. The other configurations you will see for milling use are with 4 angular bearings arranged as 2-pairs, or three bearings where two are paired up as angular bearings to withstand the axial loading, and then a deep-groove bearing near the collet to take high radial loads (usually a 6000 series bearing). As long as they are not all axial thrust bearings, the nuances between the different configurations for milling changes the run-out of the shaft under different loading configurations, most of which will give tolerances that are not signficant when milling wood with a 1/4" or 1/8" bit, but can be a factor when looking for tight tolerances in cutting metal, or if tiny bits are used (and 1.5kw would be overkill then anyway).
