ALSGS Power Feed – How Fast Is Each Increment?

[Chris Edwards 1Participant @chrisedwards1]

Hi,

I have an ALSGS (AL-310S) which I believe has a speed range of 0-200RPM.

The unit is marked with increments of 0-9 (which is it’s top speed).

Am I right in assuming that each increment roughly stands for 22RPM and that if I was to consult a ‘Feed Rate (mm/rev)’ table for my milling tools I would be able to use the ‘f’ number as the RPM (depending on material and depth / angle of cut)?

Many thanks for your help and time?

Chris.

[Michael GilliganParticipant @michaelgilligan61133]

In my opinion, Chris … that seems highly unlikely

Please see page 13 of this:

https://www.aikrondro.com/wp-content/uploads/2022/03/ALSGS-Power-Feed-User-Manual.pdf

MichaelG.

[Chris Edwards 1Participant @chrisedwards1]

Hi Michael,

Thanks for getting back to me so quickly.

Page 13 seems to be the end of the trouble shooting section and the circuit diagram (which is beyond me to read).

Do you know what the increments of the 0-9 dial are or can you explain this page to me?

Many thanks,

Chris.

[JasonBModerator @jasonb]

As these feeds get fitted to machines with both metric and imperial leadscrews there is no specific revs per mark.

Best thing to do is get out your stopwatch and time the travel over a given distance which will allow you to work out the feed rate at each position. That is what I did with my SIEG ones.

If your tools give a fz figure then you can work out a feed rate using that and the cutting speed for the material and tool diameter to work out a ball part feed rate.

[Michael GilliganParticipant @michaelgilligan61133]

The circuit diagram shows a brushed motor, with a simple control circuit

… inherently likely to have a non-linear relationship between the numbers and the motor speed.

MichaelG.

.

I’m sure the experts will be along soon to explain the minutiae

[Chris Edwards 1Participant @chrisedwards1]

Thanks Jason,

That’s great advice, I’ll give that a go!

Cheers, Chris.

[JasonB]

On JasonB Said:

As these feeds get fitted to machines with both metric and imperial leadscrews there is no specific revs per mark.

That does not seem correct as a statement. The ‘language’ of the screw is irrelevant to the motor and its controller.

Indeed, you would expect ‘5’ on the motor to give the SAME rpm whatever it is fitted to.

Hence, I would say there most surely is a specific rpm for each mark. The rpm increment between marks is likely to be non-linear, as pointed out above.

The feed rate produced by setting the dial to any particular mark will of course be dependent on the pitch of the screw to which it is attached.

—

A modern option is a tachometer app for your phone. See what the app needs as a reference and let it tell you the motor rpm for each dial division. Factor in your leadscrew pitch to calculate a feed rate.

[mgnbukParticipant @mgnbuk]

Hence, I would say there most surely is a specific rpm for each mark. The rpm increment between marks is likely to be non-linear, as pointed out above.

Unless the controller has some form of speed feedback, it is unlikely that the speed will be consistent with variations in load, so any markings related to speed would probably only apply to a no-load condition ?

The Chester 3 speed mechanical feed gearbox I fitted to my FB2 clone (the Chester box appears  to be a clone of the Emco 3 speed box) has feed rates shown, but checking with a stopwatch against a simple capacitive scale showed the printed values to be incorrect – they appear to have been calculated for a 60Hz motor, not 50Hz so are optimistic.

 

Nigel B.

[MacolmParticipant @macolm]

This power feed is the same generic design as the Align units (if not identical), and the circuit diagram is also near enough identical. It is a “traditional” universal motor SCR controller circuit that has been around since the 1960s, and none the worse for that if you need an effective but low cost speed controller. It is perhaps more cunning than first impressions, and incorporates stabilisation using the motor back EMF, depending for that on the magnetic remnance in the field laminations.

It is however certainly not a precise speed controller, and the characteristic of the control knob will be nearer to a logarithmic law than linear. On my Mill/Drill, the useable table speed range is approximately 0.25mm/second up to 7.5mm/second, and I find this almost always allows setting a satisfactory speed. If you must know the feed per cut, then some skool rithmetic is necessary, presuming you know the spindle speeds.

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