How to Choose a Suspension CMM Service

When selecting a coordinate measurement machine (CMM) service to measure automotive suspension hardpoints, the options may seem daunting. Suspension hardpoint CMM measurements are an important part of vehicle dynamics simulation, so selecting the right vendor could be the difference between success and failure in your projects.

We’ve been there ourselves, searching for vendors and evaluating all the options to find the one that would best meet the needs of our clients. There are many different factors to examine when evaluating vendors. Here are three essential considerations.

Location, location, location

Many CMM services will offer their services on the go, a “have FARO arm, will travel” approach. They will bring the equipment to your location, set up shop, and perform the measurements. This type of service offers a massive amount of flexibility, which can be important for some applications.

Keep in mind though that this extreme flexibility could also turn against you. Although it is awful convenient to have the vendor come to your location, it may not always facilitate the most accurate or precise measurements. The consideration here is fixturing. How will the vehicle be secured during the measurements? How will the CMM be fixed relative to the vehicle? How will they access all the required points?

Both pieces of the puzzle need to be planned carefully to ensure accuracy and accessibility. If the vehicle and CMM are mounted on a surface plate or another system that doesn’t allow for easy access to the suspension, it may be very difficult for the operators to make accurate measurements.

Questions to ask the vendor:

• How will you fixture the vehicle during the measurement to ensure it remains stationary?
• How much access will you have to the vehicle suspension when mounted?

Background expertise

Asking a butcher to perform brain surgery is a bad idea. Granted, the butcher may know how to use a blade with great precision, but the surgeon has years of education and experience that informs her ability to perform a successful surgery. In the same way, asking a CMM operator with no automotive background to measure the center of a suspension ball joint may not end well.

It’s a given that the vendor must be competent with a CMM, but without an understanding of automotive suspensions that skill is working blind. Blind skill with no understanding will not get the results you need.

On the other hand, when the operators understand the project they are equipped to make informed decisions while measuring the vehicle. They understand what it is you need to measure, they know how to get those points accurately, and they won’t get lost trying to find their way around the suspension.

Questions to ask the vendor:

• What automotive projects have you done in the past?
• How would you measure the center of a tie rod ball joint on the vehicle?

Presentation of data

You are back at the office after the measurement and open up the spreadsheet the CMM vendor sent you only to find the nomenclature is all wrong, the points are in a bizarre coordinate system, and you can’t even confirm that your points were all measured. Or maybe, the vendor delivers a file to you from a CMM software that you don’t have access to…and hence can’t open.

To ensure that you can do your job you need the data presented in a logical fashion. Vetting vendors to guarantee that they have the experience and background expertise to measure the vehicle properly is crucial, but in the end, you will have to work with the data files they send you.

Background expertise has a significant role to play here. If the vendor knows suspensions, they are more likely to provide you the hardpoint measurements in a format that makes sense. It’s not a given though, so check with your potential vendors to find out how they deliver the data.

Questions to ask the vendor:

• What format will you deliver the data in?
• How will the suspension points be organized?
• Can I choose what coordinate system the points are presented in?

Back to our story

We went through the process of evaluating different vendors, tried several of them, and ended up dissatisfied with the lack of automotive understanding. We were not content to offer our clients suspension hardpoint data that was difficult to understand ourselves.

We knew we could do better.

With our kinematics and compliance machine, we had a secure mounting platform for the vehicle, one that allowed for accurate measurements and incredible accessibility.

Our bread and butter is suspension engineering; and with nearly 15 years of suspension kinematics and compliance testing, we had the suspension expertise in troves.

We’d already worked hard to make our kinematics and compliance test data accessible and comprehensive, so we knew how to present data in a way that makes sense and allows for integration into various engineering processes.

It was a great fit.

With the purchase of an in-house FARO arm, we are now able to offer CMM suspension hardpoint measurement to our clients as a valuable add-on to kinematics and compliance testing. If that sounds like something that might help your project, drop us a line, or check out our CMM offering here.

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