Vib. Meas. of Die Grinders - Vib. Analysis Software?

[AMPCC]

Hello,

I've just been put on a case to measure and analyze vibrations due to hand-held die grinders. I've been put on a VERY tight budget. The problem I'm having is finding affordable (free?) software that can fulfill our needs in the easiest manner. I'd appreciate any suggestions!

I'm doing the measurements so that we can come up with a preventative maintenance schedule or tool alternative to reduce health risks due to vibration. We're using ISO 5349.

In order to stay within budget, I've purchased the following items from an online auction site: a triaxial Vibra-Metrics M3000 accelerometer, a fiber optic sensor for RPM, a signal conditioner, and a WebDAQ/100 (data acquisition system). The WebDAQ will output the data to an excel file or similar.

Here are my software needs/concerns:
Data filtering (I need this; don't I?)
1/3 Octave band analysis (per the ISO 5349 Specs, from 6.3Hz to 1.25kHz)
FFT
Waterfall plots (freq, amplitude, and time or RPM)

I'm looking to compare various tool manufacturers, so it would be nice if I could plot multiple tools on the same chart.

Here are some specs on what I'm looking at:
RPM range: 0-32kRPM
Vibration: around 3m/(s*s)

Thanks in advance for any help!

 

[reidh]

MATLab is capable of your required analysis. If you do not already have access to that, I do not know what else to suggest. The only other programs I have had luck with that are capable of meeting your requirements are the post acquisition software sold by DAQ hardware companies, such as InField by nCode.

Reidh

 

[AMPCC]

Thanks for the advice. I've spoken with Matlab, but my boss doesn't want to spend the money for it. I'm looking into Scilab... I'm having a bit of trouble with it now. Has anyone had any experience with this or success with it for this type of purpose?

 

[GregLocock]

Scilab will definitely do it, but I must admit I haven't tried reading time series data in.

You can actually do FFTs in Excel, but they are a bit ugly to use, and I think a waterfall plot would need a bit of thought.

What you are proposing is a fair amount of signal processing, I'd estimate between one and four weeks work to write that lot and validate it, from scratch.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[AMPCC]

Thanks for the help and support. The whole Matlab coding thing is coming back to me; it's basically the same for Scilab.

Does anyone have any advice on software filters for vibration data? Why type should I use? How do I decide?

Thanks in advance.

 

[reidh]

The filter will depend on your application and desired result.

I used a Butterworth filter for my most recent accelerometer test, but have used Chebyshev filters as well.

Reidh

 

[GregLocock]

You do realise you need a /hardware/ anti aliasing filter?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[reidh]

I was hoping that went without saying, but we all knows what happens when we ass-u-me....

Reidh

 

[GregLocock]

Yeah, I was just checking. I was thrown in the deep end to write something like this in my first job. It took several months, writing in a language that was designed for signal analysis, on hardware that was designed for the job. The basic bones worked after a couple of weeks, all the rest was spent getting it up to a level that it could be used in production.

It would be very easy to underestimate the time to develop this sort of application, particularly given that that the OP sounds as though he has little experience with the hardware, the programming language, and signal processing.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[AMPCC]

Ummm... yeah, of course I was going to use a hardware anti-aliasing filter... Ok, well maybe not really. I guess this is why I really need you all!

My boss put me, the brand new engineer, on the project. He gave me a TOTAL budget of $1000 which is nearly (if not actually) impossible to work with. This is why I couldn't buy a purpose built system... They didn't have a spare computer either. Also, nobody in the corporation has ever done anything like this... Arrrgh!

So far, I'm up to a total of about $600. I've still got to get cables and... a hardware filter. Now you see why I'm looking at Scilab (and now GNU Octave), both freeware programs. Do you know where I could get a free toolbox or code to assist with this project?

Thanks so much for understanding my lack of knowledge and the hole I've been thrown into!

Adam

 

[reidh]

Wow. $1,000? I hate to be negative, but it sounds like your boss doesn't fully understand what is needed to complete the project.

I assume that you are under a tight time schedule too, since you're an engineer (I don't think I've ever had a project that wasn't urgent).

This is maybe not the answer you want to hear, but I might recommend outsourcing this work to a lab specializing in vibration analysis. This will cost much more than $1,000, but may be the least painful method in the short term. You will have the results relatively quickly and know the work was done by people with experience.

Being a new engineer though, it may be tough to suggest to your boss to outsource this work.

Keep us posted on your progress!

Reidh

 

[Strong]

Mission Impossible!!

The WebDaq box does not have anti-alias filters. Don't waste your time with any software until you resolve that issue. You would either need to add AA filters or get a better A/D system. I suggest you outline what is really needed for hardware, software and labor and go back to your boss to get proper funding (borrow, rent, purchase), scrap the project, or hire a consultant to make the measurements.

Walt
w_f_strong [at] msn [dot] com

 

[GregLocock]

or buy a vibration analyser.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[AMPCC]

Thanks for the advice everyone.

Reidh, you're right; being a new engineer, I'm not in the place to request outsourcing the project. My boss would basically ask, "Why'd we hire you, then?!" Plus, he'd like to measure a bunch of possible replacements in the future. Other than that, I agree with your suggestion.

Greg, I'd like to get a vibration analyzer, but I don't think my boss could rationalize the cost. He can rationalize the cost of my labor... (not to mention what I do can't be as good!)

I think I'll get some AA Filters. I might just keep searching for used equipment online. Has anyone tried hard wiring a PCB surface mount filter in a cable before? It's a cheap method, but I don't know how well it would work.

Did anyone have any suggestions for Matlab type code for this project?

Thanks again everyone,

Adam