Method to cut shock absorber

[Aizzat Hasnan]

Hi fellow senior engineer, i will be starting my job as QC engineer for an Absorber manufacturing company. My first task would be to find out the method that can cut the shock absorber without physically cut it. As physical cut are quite hard to get a clean cut. Without a clean cut it may messed up the measurements for reverse engineer or for checking the manufacturer are following the specs of the design given. So, my boss suggest me to find a method such as scanning method (such x-ray) of the absorber to determine the measurements of all the dimensions without having to physically cut it. This is my first job btw, n i really hope i can do well. Thanks

 

[GregLocock]

Other than X ray, you could think about ultrasound. I suppose given $$ you might get the resolution. I'd be amazed if there is any way to measure shim stacks accurately enough to dimension them without physical contact.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[Aizzat Hasnan]

Thanks! If u do have any other method that can ease the process of measurement without having to cut the item, do let me know.

 

[BrianPetersen]

What are you inspecting for, that requires the damper to be opened?

Do you have a shock dyno? If there's question about the proper shim-stack being used, or the correct oil viscosity or level being used, a shock dyno will turn it up if you know what you are looking for.

 

[Aizzat Hasnan]

More on the measurements of every dimensions outside as well as the inside parameters of the absorber. To ensure the manufacturer did it as precise as the design required to avoid future problems. If u guys has any link that can allow me to understand more the process. It would be great help

 

[3DDave]

It's probably better to sample in-process rather than waiting to find defects in the end product. Also, performance testing is more often used than dimensional for finished product. See if the shock absorber does what it is supposed to do.

If you have an independent supplier that you don't trust to meet the requirements then find a waterjet company and commence to slicing. It won't distort the parts.

 

[SwinnyGG]

Alternatively, use a pipe cutter to cut the shock body. You'll get distortion on the OD but who cares.

 

[3DDave]

It occurs to me that using substandard materials is the more likely deception. Meets the dimensions with garbage substitutes.

 

[BrianPetersen]

Having had customers that build automotive and motorcycle/snowmobile dampers, and having bought (and raced) a few myself ...

Destructive testing is never part of the production process. Parts go through inspection stations before they get assembled. The critical parts of the process are automated ... if the shim-stack station runs out of a certain shim, it stops and turns on a flashing light and a buzzer. Oil is pumped in using a metering pump that logs the correct quantity. At the end of the ilne, the run-of-the-mill dampers go through an automated function-check station that cycles them a couple of times to make sure the force in response to a certain actuation speed is within bounds. The high-end dampers go on a shock dyno.

If you work for the same facility that builds the dampers, go down to the production floor and see what they're doing. If you are an end-user who is subcontracting them out, make some phone calls and arrange a site visit.

You can't solve a problem that hasn't been defined, so you need to define it. "How to cut the shock absorber" begs the question WHY you want to do that. "To check the dimensions inside" - WHY do you want to do that (and go down to the production floor and measure the parts before they get assembled and there's your answer). "Because we are getting inadequate performance / leaks / premature wear / ???" - WHY is that happening?

It may turn out that you do indeed need to cut one apart - but the method by which you do so, will depend on what you are trying to establish by doing so. You also need to establish exactly WHERE you need to cut it apart.

Waterjet will do it with minimal damage - but it's not good if you want to know how much oil is inside it. A hacksaw will do a messy job - but if you cut it apart at the opposite end from where the dimension is that you are interested in, maybe it doesn't matter.

 

[LionelHutz]

So, you're trying to reverse engineer dampers from other manufacturers? You'd be able to sample the internal parts on the production line if you are actually working for the manufacturer.

 

[Aizzat Hasnan]

Thanks for all the suggestions. Truthfully i just enter this company, n this is literally my first task. I need to get more information on the task itself. Right now I'm just compiling data for the scanning method for measurement purposes to be presented to my boss this friday. Still got many things to learn. I do appreciate all of your opinions.