With Redline stating they have a new recommended warm up cycle will the spindle warm up button on redline controller be updated to the new cycle @RTCNC
where did you see this?
I expect that’s a yes, but my question from yesterday as to when has yet to be answered. Gotta go back to running my original g-code program I created before they released the bacon button version of the software.
In a future firmware update, most likely
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Thanks, didn’t see that one
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I have to admit I’m on the fence about whether to make this change myself. While their reasoning about lower speeds being beneficial to give the bearings time to warm up more evenly seems sound, I’m concerned that an important aspect of air cooled spindles is being ignored. Namely, air cooled spindles are only cooled by the fan that’s spinning at the spindle’s RPM.
In my mind there’s a bit of a thermodynamics problem going on here. If you lower the initial speed that much in an effort to “give the bearings time to warm up and grease to distribute”, you may actually be causing a proportionally much higher amount of heat to be put into the spindle in the first 5 minutes than you would have otherwise in the first 10 of running it at 6000rpm because the fan is not spinning as fast and so things will get hotter faster.
In the case of water cooled spindles, this would be completely fine because the cooling isn’t tied to the RPM of the spindle. But for air cooled spindles, a minimum RPM recommendation by the manufacturer isn’t just to account for reduced torque at lower RPMs, but also because the spindles can burn their motor windings if the motor is run so slow that the fan can’t keep them safe from thermal damage.
For anyone who has made the switch, have you noticed that after 5 minutes your spindle is much hotter than it was at the same time in the previous warm up routine?
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I did the new warm up routine for the first time yesterday
It made no difference to the bearing noise.
I’m no engineer but because the noise comes and goes ( see video in previous post) https://forum.onefinitycnc.com/t/spindle-noise-update/37440/11?u=ken5
I think that one or two of the bearings aren’t round and are dragging
Or maybe it needs more grease
Either way I’m close to buying a different spindle since Redline says this is normal
I bought a spindle because the Makita router was too loud and the spindle would be much quieter ( I even think someone posted a decibel reading between the two)
But that’s not what I’m experiencing
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If your bearings have been damaged (or were already damaged when you got the spindle), then I wouldn’t expect the spindle noise to go away with a new warmup routine. My spindle makes noticeably less noise than what you posted in your video. I feel like once it’s warmed up, most of the noise I get is just from air movement from the blades on the fan. For my part, my spindle only squeals slightly during the initial 6000rpm phase of the warmup and then becomes completely smooth sounding by the time the warmup is done.
My main concern with the new low rpm startup guidance is that it is likely going to cause the motor windings to be subjected to a lot more heat than the previous warmup routine. That feels at odds with their stated objective for why they were making the change. Whether the windings can withstand that long term, I can’t say. But regardless of ceramic bearings or not, lower RPM means longer “on time” for each of the coil windings and because the fan is also going to be less effective at lower speeds I’m currently expecting the spindle to overall be hotter after the first 5 minutes of warmup compared to the first 5 minutes of the old routine.
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Personally, I think the whole warm-up thing is a little overblown. How much can one warm-up cycle really differ from another? Many users don’t do any sort of warm up at all, and I don’t hear about spindles getting fried very often.
I warm mine up, just because that’s the mainstream thinking - but I do so without being fully convinced its necessary. An infrared thermometer to the exterior of the spindle shows it gets up to about 30-40° Celsius. Then when I start cutting, and coolant starts flowing in my watercooled spindle, the spindle exterior drops back to 22° C real quick. Making the whole warm-up thing seem a bit pointless.
@MoarVoltz I don’t think the low rpm in the warm up is likely to damage a bearing. A spindle motor under no load seems to me like it would never get hot enough to cook a bearing. Especially within a 30 minute timeframe. I think you make some good arguments about reduced airflow, but I just don’t think the motor is working hard enough to ever get there. You might be able to consider the cold spindle body as a large heat sink during the warm up that counteracts what little airflow there is? 100% opinion and 0% fact based.
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Well that’s sort of the point. The temperature of the exterior of the spindle case is much more about the heat from the windings than that of the bearings. The warm up is intended to warm up the bearings and grease to an operable temperature, but ideally you don’t want your windings to get HOT hot, so there’s a balance to be struck. The new numbers feel a bit pulled out of thin air to me. I’ll probably just add another stage of 3000 rpm before the original warmup routine and call it good.
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what are you using for the Gcode for pause? i tried it myself and from the redline panel but for some reason mine is just skipping the pause each time.
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I’m not using a redline controller. So I don’t know if it behaves differently for some reason. I’m still using the original code that redline had in their manual.
ah i’m using the controller and for some reason mine refuses to obey the pause mcode
Solved in version 1.4.18!
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