As mass customization becomes the rule rather than the exception, distributors and parts manufacturers are looking to eliminate costly vibrations from their customers’ machining operations, or from their own production lines, reducing or eliminating the need for secondary operations.
The reason for adopting this strategy is simple: problematic vibrations are common when manufacturing metal parts. Vibrations affect tool life, surface finish, and add time and cost to job completion. Such conditions often lead to the setting of sub-optimal machine parameters, or to the use of expensive “de-vibe” tools.
Vibration occurs most commonly when the overhand length-to-diameter (L/D) ratio of a tool is high, a requirement of tooling needed to reach into deep pockets, holes or other features of the part being machined.
As the part rotates around the tool, or vice versa, the result is vibration that yields poor surface finish and requires secondary operations to meet specifications.
With productivity goals becoming more ambitious, having a vibration dampening tool holder that performs without having to be tuned for each job can provide tangible benefits to parts manufacturers. As additive manufacturing (3D printing) becomes more widespread, the need is growing for longer, more flexible tools more susceptible to vibration than shorter tools.
An effective way to improve the bottom line is to use tool holders that feature self-tuning mass dampers (STMDs). These unique tool holders consist of a tungsten mass supported by polymer discs inside the holder. The discs extract vibration energy from the cutting tool body to minimize movement and neutralize vibration by connecting the machine tool motor and the cutting head.
As cutting forces are applied to the tool, vibration occurs naturally on a frequency band, and the stiffness of the STMD self-adjusts to that frequency to maximize the effects of mass dampening.
STMDs are elegant plug-and-play solutions that are easy to use for improving surface finish, accelerating cycle time, decreasing tooling costs (Total Cost of Ownership), reducing scrap rates and decreasing energy consumption. By enabling the completion of jobs faster and more efficiently compared to other options, STMD tool holders can improve feeds and speeds due to stabilized tooling and can also improve workplace morale by relieving stress.
Because machining operations often use high L/D ratio tools, vibration can be a challenge. STMDs extract vibration energy from the cutting tool body to minimize movement and neutralize vibration.
In many instances, tool holders require maintenance and tuning. In contrast, STMDs are maintenance-free. Given the volume of machining operations in most shops, even the smallest percentage reductions can result in substantial savings while allowing shops to meet increasingly tight production schedules.
The Details
The use of STMDs is an example of physics and chemistry working together. The complex problem of changing vibration frequency on cutting tools is due to changes in cutting conditions, such as tool wear, wearing joints and vibration of work piece materials. Traditional tool holders require continual tuning to ensure top performance, as out-of-tuning condition could make the vibration problem worse, instead of improving it. In contrast, STMDs are self-tuning and can work with any setup in a production facility.
Specifically, the spring elements adjust stiffness according to vibration frequency and overcome the problem of frequency changes. The result is better surface finishes and higher process reliability.
Because all machine tools are different (big, small, long, short, new, old), variation makes the machine tool’s vibration frequency unpredictable, as various tools vibrate at multiple frequencies. Currently, mass dampers on cutting tools are difficult to use because they are tuned to a specific frequency or they need frequent tuning to ensure vibration dampening efficiency.
STMDs contain materials that change their stiffness according to vibration frequency. When frequency is high, stiffness is high, and vice versa. These materials enable the self-tuning function on mass dampers, adapting automatically to machine conditions.
Using a turning tool as an example, the tool may be set up for different lengths for machining different parts. The longer the overhang length, the lower the vibration frequency and vice versa. The tool will vibrate at different frequencies, depending upon overhang length, and STMDs over a wider frequency range correlated to L/D ratio.
Cutting process parameters (speeds and feeds) are conservative, or limited, when the risk of unstable variation is a consideration. When using STMD technology, vibration is a non-issue.
Additionally, when high speed machining excites multiple frequency variations on cutting tools, STMDs adjust themselves to dampen high and low frequencies, so it becomes possible to cut successfully at high speed and feed rates.
A Practical Solution
STMDs offer near-perfect surface finishes compared to the most widely used tool holders. The difference is in the tungsten mass supported by polymer discs inside the holder, as tungsten is a dense material that remains stationary compared to other metals and plastics used to make tool holders.
As noted previously, this tooling solution has an elegance – practical simplicity — that makes it easy to use and results in improved surface finishes and cycle times, as well as in lower tooling costs and less re-work.
There are machining test data and a white paper that explain, in detail, the performance of STMDs under various conditions and show that they are an alternative to traditional tool holders that is worth considering, especially given the increasingly high cost of failure to stock products that customers want, or the cost of having to do re-work because a part or component does not meet specifications.
STMDs are an economical alternative to other de-vibe tools, which can cost up to $10K/unit, and can help you reduce the number of damaged parts while improving surface quality and prolonging the life of cutting inserts to help minimize your production costs.
After you’ve figured out your workflow and programmed STMDs in your CAM software, you’ll see how well these mass dampers integrate with your processes. You’ll also experience a reduction in tooling breakage that can reduce your cost of ownership by as much as 30%.
STMDs can also help your customers, or you, reduce cycle times by 30%, lower tooling costs by 5%-10%, decrease energy consumption by 2%-3% and reduce scrap by 1%-2%. With the volume of machining that you or your customers do, those numbers can be significant.
Besides manufacturing a valuable product, we pride ourselves on the support we provide to distributors and production facilities alike. If your customers or you need assistance with using STMDs, you can send your machine and machining setup details to info@maqab.com and we will respond within 24 hours. We make that promise because we know how important it is to finish a jobs on-time and on-budget, and we know first-hand how expensive it is when jobs need re-work.
To begin a conversation on how we can work together, tell us about your customers’ vibration dampening challenges, or those that you’ve experienced recently.
The MAQ Story
The idea for MAQ STMDs came from Qilin (pronounced CHILL-in) Fu, our CTO, when he was a doctoral student at KTH Royal Institute of Technology in Stockholm. He studied how vibration affected machining and realized there were opportunities for improvement.
A breakthrough occurred in 2015 when Qilin used existing polymers for accurately measuring a polymer’s frequency-dependent stiffness. He found that some polymers have a substantially increased stiffness with increased frequency.
Eventually, a research team that included Qilin determined that a group of polymers with a specific physical structure and chemistry would have the necessary frequency-dependent stiffness for mass damper applications.
As for the company name, MAQ, it comes from the first names of the three co-founders – Mihai Nicolscu, Amir Rashid and Quilin Fu.
It is an excellent example of basic research in an academic lab leading to a great business idea which then became a thriving business.
If you believe STMDs can benefit your customers, let us know so we can discuss how we might work together.