Spindles - the basics for a beginner
Having gotten to grips with a spindle installation over the last few months, I've realised that there is more to them than what the SB community may have been led to believe. This is a thread that will try and sketch the bigger picture around spindles for CNC routing duty. Here are some coarse notes......
Spindle -choice of power curve -choice of total power -choice of max speed (bearing types) -choice of bearing types in relation to thrust/side loads -Collet nut, collets, wrenches -Cooling system, either: --Shaft mounted fan (very noisy), or --Separate motor fan (very quiet), or --Water-cooled or Compressed air injection -Temperature detector, either: --Thermo switch (Klixon) wired to VFD --Thermistor, wired to "thermistor relay" --External thermometer (infra-red or contact) Thermistor Relay (if spindle fitted with thermistor) Variable frequency drive - Voltage - Single/3-phase - Frequency range - Remote display - Remote speed input - Can it send/accept fault signals - Cooling - Dust resistance - EMI filtering/shielding needed EMI filtering/shielding: - Reactors - Ferrite toroids - filters - shielded cables - housings for reactors, toroids, filters Any more? |
Great questions.
Now I need the answers!!! ..................Mike |
Sorry if this is the wrong place for this question!! So I moved it! :-) GD
Is there a "Dummies Guide' to spindles? What is the difference between the spindle and the router? I understand that the spindle has some sort of 'control' box. I also understand a spindle needs some time to warm up, and some time to cool down. Apart from possible quality benefits in cuts, what is the other advantage of spindles? Is a spindle more reliable? Is it comparable to a VW against a Land Rover type of thing? Thanks ............Mike |
Not quite VW against Landrover - more topical comparisons are Skil-saw versus bench saw, or portable drill in stand versus drillpress. A router motor has the same construction as Skil-saws and portable drills - they have brushes and the speeds fall off a lot as the load increases. A spindle motor is similar to that used in benchsaws and drill-presses - they have no brushes and the speeds stay pretty contant, irrespective of the load.
The "control box" for a spindle changes the frequency of the AC power fed to the spindle (or benchsaw or drillpress) and that changes the speed. You could plug a spindle straight into mains (3-phase) without using the "VFD control box" but then your spindle will run one speed only - 3000rpm in Europe, 3600rpm in the Americas. The Variable Frequency Drive controller increases the mains frequency to give higher speeds. (for routers, one fiddles with voltage (instead of frequency) to change speeds) Routers are built cheap, nasty and disposable. Spindles are built to last longer. But they both have to have bearings and this is the Achilles heel. Spindle guys use more expensive bearings, but they aren't that much better than router bearings (not by as much as the price differential would indicate). So, if you want a decent life out of spindle bearings (or any bearings for that matter) you need to nurse them. Not mandatory, but highly recommended. Cut qualities don't improve dramatically when using a spindle over a router, unless you had a pretty bad router to compare it with. Spindles are very much quieter, if they don't have their fans mounted on the main shaft. They have more torque/power (the router guys can tell very inflated (2x) lies about their power). Collets for spindles are more readily available. |
Ok! Let me ask a supplementary question or two.
A spindle + VFD costs a great deal more than, say a Metabo G700. In fact I could buy more than 10 Metabos for the price of 1 medium price spindle set up. If I am doing only relatively light work, but frequently, 4 hours + a day, which way would you go? In particular, I have read about suggested problems when peck drilling with spindles. You say spindles need nursing more. If you employ a Van, would you also take this into account? ............Mike |
Mike
Running a spindle for 4 hours + a day is far nicer than a router as they are extremely quiet? unless you have an enclosure like Geralds Shopbot. Paul |
My new workshop has an enclosure http://www.mechmate.com/Forum/clipart/smile.gif
No maid though ............Mike |
There is an advantage to ordering a spindle with a tool changer carriage. It comes with a quick couple as opposed to a collet. This will allow you to quickly remove bits with a counter clockwise twist, and downward tug. No more messing around with wrenches. No more time spent zeroing bits. Saves loads of time and wear on the knuckles. Did I mention, "NO More Tool Zeroing"?
If you invest in a few tool holders, they aren't cheap, all of your bits would be setting there, pre zero'd and ready to go. Just a thought |
There is anadvantage to ordering a spindle with the optional tool changer carriage. This comes with a quick couple as opposed to a collet. Now you can change out a bit with a counter clockwise turn and a dwonward tug. No more messing around with wrenches and no more time spent zeroing bits.
If you invest in a few tool holders, they aren't cheap, your dedicated bits would be setting there, manually zero's and ready to go. Just a thought |
Some laser cut wrenches for ER25 collet ($2.50 ea)
http://www.mechmate.com/Forum/messages/47/1986.jpg http://www.mechmate.com/Forum/messages/47/1987.jpg The file that can be given to a laser-cutting company <table border=1><tr><td>http://www.mechmate.com/Forum/icons/attachment_icon.gif SPANNERS.dxf (94.0 k)</td></tr></table> |
Joe: An added advantage as I see it is also no more micro movement of the gantry from torquing the wrenches. My question at this point, having had my spindle with the above pictured ER25 is: Can I convert it over to quick change? I admit that this is a question I am asking before doing any research on it myself. Combination of laziness and overwork.
Dave |
Hi Dave
I wouldn't think so as the mechanism to allow the tool change is part of the actual spindle with the release mechanism on top being air operated. The spindle also needs to have a matching taper to take the tool holder. The costs of such a modification would be excessive, ie an entire rebuild of the unit. The advantage of a unit with tool changer is that you will be able to handle much more complex jobs that require many tool changes. I have worked on machines with both options and found that you can cope without it, if your work is well planned! The question is how complicated do you want to get and at what cost? Alan |
Alan: I had a feeling if it was easy I would have seen some "how to" threads in one of the forums a while ago. I think I'll wait until my Columbo is burnt out and just get a different model later.
I would be willing to bet that an adaptive collet could be designed to quick change bits without a wrench though. By the time you got through you would probably have an exra inch or two from the spindle to the end of the collet but raising the z is the easy part. This could get interesting. Dave PS: This probably takes the thread past the depth of the topic title but seems an appropriate drift. |
Gerald, Can you please let us a have a few links of spindle manufacturer's in Italy.
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From a google on "elettromandrini" (electric mandrels, spindles), here are some
http://www.eltesrl.com/inglese/index.htm http://www.fimec.it/ http://www.hsd-hitec.com/eng/cont/elettromandrini.asp http://www.elettromeccanicagcolombo.com/home_en.htm Etc..... (most of these websites are difficult to follow, and the products that may interest us are not obvious from the on-line catalogues) These companies may, or may not, have sales/service agreements with people in your territory. Prices(and service) could vary depending on the channels (and quantities). Also remember that a spindle needs a variable frequency drive and maybe also temperature protection and electric noise filtering. It is not just a case of buying a spindle and plugging it in. |
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Wow just got a price for a 2kW spindle at www.fimec.it under 600 Euro's plus the VFD off course but still way cheaper than I anticipated. So I'm thinking Spindle now... hehe
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Kim proceed with caution. Apparently the life of "spindles" is around 2-4 years before the bearings wear out. The normal practice with the low cost spindles is supposedly to throw them away and purchase a complete new spindle! They say that there is nothing inside that you can repair yourself. (I would dearly like to find the graveyard of dead spindles....)
Most owners of spindles are very careful to extend the bearing life....They warm them up before putting on loads, they check the bearing temperatures often, and they program the cutting so that cutter loads are applied gently and not suddenly. |
Gerald, to begin with I'm not sure how much the machine is going to cut, but I still think I'm going to invest in a spindle and a VFD. The VFD is a good buy so that I can supply another spindle in time with it. But now we'll see what happens in the near future...
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I know how you feel......we have some of those "inexpensive" spindles. A Fimec that has run for a year and two HSD's that havn't run seriously yet.
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Gerald. The Fimec seems to be a good choice for my use at the present time, when it becomes nessecary then I can change into a better and more expensive spindle at a later time. but for now the Fimec is a rather good choice to get a spindle for the first machine in my garage... :-)
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What is the spindle (make,model)that you could recomend which has good value for money.
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These are the elements in a typical spindle system:
The red items are essential, the VFD and the Spindle. Blue is fairly standard - there is a form of temperature sensor built into the spindle and this is meant to shut the VFD down if the spindle overheats. Some sensors are incompatible with the VFD's and a special relay then needs to go in between. We are typically talking of fan cooled spindles. The fans are either shaft-mounted (S) or driven by a seperate electrical motor (E). Shaft fans get noisy at high speed - electro fans are quiet. VFD's make a lot of electrical noise. One of the effects of this noise is more heating in the Spindle. Reactor A cures that. Other effects of noise are false signals to the controller and other electronics near your workshop - you may need B, C, D and E as well.... |
OK, I now have a complete spindle package pricing from Fimec, actually not that expensive.
I need to pay 558 Euros for a 2kW 18000 RPM spindle. I need to pay 350 Euros for a Type R VFD from Fimes also can take up to 2.2kW spindles. And at last I need to pay 65 Euros for Transport to Denmark. All in all I need to get 973 Euros then I have both the VFD and The Spindle with a R25 Collet on it. I thinnk this is very cheap considering what I thought it would cost me. |
Kim, realise that you can connect a bigger 3.5kW spindle to that 2.2kW VFD. Sure, you will only get 2.2kW max power, but you will have a spindle that can be moved to a bigger 3-phase VFD if you want to one day.
You will still need to buy, at minimum, a collet nut, some collets and some wrenches to hold the nut and shaft (see photo's above). Also, the single-phase VFD's are well-known to make lots of electrical noise - your neighbours won't like flickering TV's. Be prepared for some filtering - I think Fimec sells filters as well. |
Gerald. The spindle as far as I know comes with the NUT installed, all I need to get is the collet and the wrenches I see I can cut on the laser at work. SO this should present a very little problem.
I don't know how much electrical noise a VFD makes, but as far as I know then filtering shouldn't be something that has to be done but otherwise I can get it from my dads work as they use alot of VFD's there also. The only reason that I'm buying it from FIMEC is that it is from their range and then I know it will work with their spindles without any problems. |
Kim I have been looking at the Fimec site.
Which model spindle and VFD did you choose? |
Hello Greg....
I have to get to my computer at home to get the excact number of the Spindle, but the VFD is the Series R VFD's up to 2.2Kw I'm almost sure that the Spindle is on their online catalog the one called HM73-060 1.8kW, but it is a 2kW spindle.... |
Thank you Kim
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Hi Greg...
Sorry I totally forgot to get the very right numbers for you to the FIMIEC Spindle. The Excact model is. Hm73c-070 shaft type P. Kim |
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