DIY dynamic spindle balancer project

[rhb]

I've started on an electronics project to implement a dynamic spindle balancer. I'm not going to discuss it here as it seems unlikely that it complies with the rules for this forum. On the other hand, such a device is only of interest to machinists and from an electronic enthusiast perspective not very interesting. Cost should be under $50. I hope the moderator will permit my announcement.

If your are interested you can read about it and participate here:

[email protected] | A spindle speed and balance indicator proposal

groups.io

Have Fun!
Reg

 

[DDoug]

IIRC this has been discussed before, check the archives

 

[rhb]

Well after 5 pages of search results I found nothing relevant.

Most of the hits were on "spindle". So I'll go back to working on the software. It's an Arduino project at 12-15 yo level. But not very many kids have a use for one. And I suspect most machinists don't have the interest to fool around with an Arduino. Sort of falls in the cracks.

Reg

 

[eKretz]

Well after 5 pages of search results I found nothing relevant.

Most of the hits were on "spindle". So I'll go back to working on the software. It's an Arduino project at 12-15 yo level. But not very many kids have a use for one. And I suspect most machinists don't have the interest to fool around with an Arduino. Sort of falls in the cracks.

Reg

We discussed it some for sure in the Abrasive Machining section as regards balancing spindles and grinding wheels. Here is one thread I participated in a discussion regarding balancing for sure:

Anybody familiar with Drukov grinder?

EKretz: I just found this post, as I was searching for information about this same unit I have. Mine is single phase motor. I have the manual I got with it. I purchased it new ~1994 or so from Enco. It came in a big wood box intended for storage. You said you found the manual for it via google...

www.practicalmachinist.com

 

[rhb]

Any discussion of *building* a device and writing software for it?

While I am focused on balancing faceplate work on a lathe, the gadget is applicable to balancing *any* spindle. My other concern is balancing backplates for unmentionables running at 2000 RPM.

I just finished a 3rd pass on the pseudo-code for the program to run the thing. I'll order parts tomorrow and start writing C code Tuesday or Wednesday, subject to diversion to another destination at a mere whim.

I made the decision that showing both RPM or SFM was very desirable. The former for facing work and the latter for normal turning. Not quite willing at this point to interface with a DRO and the motor to adjust SFM for a facing operation. Easy to do except for finding out how to talk to the motor speed control and the DRO. That would be very machine and DRO specific and involve reading far more documentation than I'm willing to do without a $$$$ contract.

 

[eKretz]

There an app for 3-pass balancing that I use. I mentioned it in that thread IIRC.

 

[rhb]

OK, I saw several mentions of the Apple app. I disregarded it as it is a rather expensive solution for someone who neither has nor wants an iPhone. Thanks for the clarification.

My project is creating a dedicated <$50 device which one can install permanently on a machine for both balancing and providing automatic SFM readout.

 

[EPAIII]

This forum may not be the best place to ask but not for the reasons you think. First, I am not a moderator here, but I doubt that they will object to this discussion unless it goes in a direction that is stated as not desirable in the forum rules. One big thing that is banned is discussions about imported/hobby style machines.

You fear that the members here may not have any interest in electronics or computer code. That is not true. While some may be real novices in electronics, others are quite adept. And CNC machining, which is the current way to go in commercial machining does have it's programming aspects. So that also is probably not a problem.

However, this board is mainly for the use of professional machinists, not hobbyists. They are primarily devoted to making money in professional shops. So you may not get the types of responses that you need. Or, you just may. Don't let this stop you.

However, I will suggest another BB which may generate better responses. It is more of a home/hobby machinist board, although there are professional machinists there as well.

General - The Home Shop Machinist & Machinist's Workshop Magazine's BBS

This forum reserved for general machining discussion. Off topic threads are allowed, but will be closed if they go too far off track or become too numerous. Please add “OT” to the title of any off topic thread. Discussions on religion or politics are not allowed.

bbs.homeshopmachinist.net

I will be following your link and may have comments after that. I am curious about the details. One thing that immediately comes to mind is that many spindles are mounted in very heavy castings which are a part of an even heavier machine. These machines are deliberately constructed to prevent even the smallest vibrations because those vibrations can cause problems in the way they cut metals. So, if a spindle is going to be balanced in place, then you are going to need very sensitive sensors. Good luck with your project.

BTW, the search functions on this and other internet BBs are rather poor. I and others have found that you can find things on the BBs a lot better by using the well known internet search engines like Google, Bing, DuckDuckGo!, etc.

I've started on an electronics project to implement a dynamic spindle balancer. I'm not going to discuss it here as it seems unlikely that it complies with the rules for this forum. On the other hand, such a device is only of interest to machinists and from an electronic enthusiast perspective not very interesting. Cost should be under $50. I hope the moderator will permit my announcement.

If your are interested you can read about it and participate here:

[email protected] | A spindle speed and balance indicator proposal

groups.io

Have Fun!
Reg

 

[Garwood]

Interesting. A vertical shaft balancing machine is on my to do list. I make stuff with Arduino and RPI products in them, but I know very little about the coding part of it. Not my part of the products.

I would think trying to balance anything on a lathe spindle would be a waste of time unless your lathe wasn't much of a lathe. From my understanding of how a balancing machine works, a lathe spindle is the opposite.

And I disagree with the assumption that you need extremely well balanced parts to get accurate results in a lathe. I have made lathe fixtures for 20+ lb offset parts and balanced them by welding on chunks of steel bar until I could run the desired RPM smoothly. No way it was balanced within a lb or so, but it spun up just fine and finished a 3" bore to a couple tenths tolerance no problem.

I've made many thousands of steel flywheels. Average finished weight around 65 lbs. Blank starts about 100 lbs. No vibes at all spinning those saw cut blanks 1500 RPM, but if they aren't balanced afterward they do present issues spinning to 6000+ RPM in their use.

 

[rhb]

First of all, I was *not* asking a question. I was merely stating that I was engaged in a project which *might* be of interest to a machinist and further details were available on a mailing list.

I am certain that there are people here who are proficient in electronics, just as there are people on EEVblog who are proficient machinists and EEs. Much hilarity ensues when someone skilled in both posts there and those ignorant of machining comment. But it gets repetitious.

I visited once but did not find the HSM forum interesting. I've never been back.

The ADXL355 3 axis accelerometer has a 20 bit ADC, that's 1 part per million resolution. An eval board for those is $45. An ADXL345 has 10 bit, one part per thousand resolution. But eval boards are $2-3 on ebay. The 345 is the most likely chip in an iPhone. As the software changes are minimal I'll try a 345 and buy a 355 if I decide I want finer resolution. Likely I'll get a 355 because I'm a bit obsessed with precision.

As a retired oil industry seismic research scientist/programmer who started with punch cards in 1971 I am agog at what can be bought today for a few dollars and what one can do with it. The Cray supercomputer of 30 years ago fits in your pocket.

Edit PS: How big a displacement do you think a reflection from a rock layer 5 miles below the surface of the ocean produced by discharging compressed air into the water is? That was what I dealt with, but we never looked at it in terms of displacement so I can't give you a number. We just cared about what it was relative to other reflections. But I can assure you that the vibration of the smallest, best balanced spindle in the heaviest machine ever built is huge by comparison.

 

[technocrat]

$150 gets you a commercial one with high sampling rates and mature software. The RC guys use them a lot to get best performance out of their toys. This one is in it's second commercial version, all the bugs ironed out and software updates as more features are added. https://dynexhobby.ashop.me/p/91642...-balancer-spectrum-analyser-oscilloscope.html

 

[eKretz]

OK, I saw several mentions of the Apple app. I disregarded it as it is a rather expensive solution for someone who neither has nor wants an iPhone. Thanks for the clarification.

My project is creating a dedicated <$50 device which one can install permanently on a machine for both balancing and providing automatic SFM readout.

Not an Apple app... The app I mentioned isn't used for the actual vibration analysis, only for calculation of how much weight and where to add it. I use a Bruel & Kjaer accelerometer and charge amp and an oscilloscope for amplitude and frequency measurements. The app is only for determining the amount of and where to place the weight.

Your idea is worthwhile, and I'd be interested to see how it pans out. Don't really feel like joining another io group though. I'll set a bookmark on it.

 

[rhb]

@technocrat: Thanks. That looks to be a commercial version of the Qvale

DIY - Dynamic Motor and Prop Balancer - ItsQv

www.itsqv.com

But it's a lot more than $150 by the time you get all the bits for a working system.

A friend built the Qvale. Both his metal shop and electronics lab dwarf mine. I had not read the datasheets for the AD parts in a long time. A review shows a resonance at 2.4 kHz which may pose a problem at the upper speed range.


I'll make another post to this thread when I've got a working unit.

BTW No need to join the list to read it.

 

[rhb]

LoL!

I was searching Amazon for an LVDT indicator sensor, e.g. B&S 599-988, and in Amazon's infinitely mysterious fashion I got this:

https://www.amazon.com/%E3%80%90WT901C-TTL-Inclinometer%E3%80%91High-Performance-Acceleration-Sensor%E3%80%90Kalman-Filtering%E3%80%91/dp/B01N03WKDV

as the 3rd item and a soap dispenser as the 5th item.

I'm ordering one. It's probably all I need for balancing faceplate setups. All the smartphones have an IMU so the market for them is billions of units per year and there are a slew of different models from the usual suspects such as Analog Devices, Bosch, etc with accuracies from parts per thousand to parts per million.

I'll report my test results after I get it.