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Manufacturing — especially for smaller operations — is a game of inches. The margins between competitive and non-competitive, successful and unsuccessful are thinner than the metal chips your machines throw.

That’s especially true now. Digital technologies are reshaping the business landscape, transforming our industry and making it easier to pay attention to (and iron out) the little, inefficiency-inducing details that might in an earlier time have slipped by unnoticed.

Today, let’s talk about 5 hidden problems that inhibit your shop’s machining efficiency, and explore what you can do to correct them.

Problem 1: Premature tool wear / failure.

Sometimes, a tool will fail before it achieves its desired amount of flank wear. Also known as “tool cutoff,” it’s akin to life expectancy.

When a tool breaks or chips below its rake face during a cut, it can create defects in the finished product, wasting your shop’s expensive raw materials, machine time, energy costs and labor hours.

Your simultaneous manufacturing efficiency goals, then, are to maximize the amount of work your machine tool can accomplish before it wears to its cutoff point, and prevent it from prematurely failing.

What you can do about it:

Conduct a machinability study to determine what’s causing your tools to break or wear down faster than expected. Then, use the results to program your machines such that they avoid the problem.

As a tool dulls with use, power factor (K) — the amount of horsepower required to remove one cubic inch of material in one minute — will rise. If you have a tool condition monitoring system in place, you can monitor power factor and correlate it to tool cutoff, to establish an indicator of imminent tool failure.

Once you know that indicator, you can set a computer limit that automatically forces a tool change before the tool’s failsafe point is reached. This could help your shop prevent sudden failures and reduce your input losses.

You can also monitor and correlate other factors — including acoustic outputs, vibrations at the tool site, strain, and temperature — to further refine your shop’s means of detecting and preventing undesirable changes in state during its machining operations.

Problem 2: Chatter

Every tool holding system — comprised of the cutting tool and tool holder — has an inherent, natural frequency. And, because they’re among the most flexible bodies on the machine tool assembly, they can easily begin to resonate, or “chatter,” during the normal course of operation.

Chatter rates and amplitudes can be affected by the stiffness of the workpiece and by the tool’s overhang in the spindle. They can also be influenced by the number of teeth in the tool, the cutting parameters used, or other factors.

Chatter creates waves in the machined surface, which in can in turn reduce the quality of the completed part (or make it unusable). Chatter waves also cause the machining process’s next cutting edge to experience a variable load, which increases wear on that edge and potentially exacerbates the chatter itself.

Left unchecked, chatter can reduce the life of the spindle itself, creating the need for a costly, preventable repair. Most shops try to prevent chatter by keeping their machining speeds low, but doing so might impose an unnecessary limiting factor on your throughput.

What you can do about it:

You could conduct a tap test. In a tap test, an accelerometer is attached to the end of the cutting tool. The cutting tool is then struck with an instrumented hammer that contains another accelerometer.

Using special algorithms, a data acquisition (DAQ) unit plots out a stability lobe diagram [pictured] which plots the ranges in speed at which the tool is not expected to cause chatter.

Based on that data, operator can then choose a higher spindle speed that would still be less likely to cause chatter. Similarly, thin-walled parts may also be tap tested to help align spindle harmonics with part and fixture harmonics.

Therefore, instead of tool strength and spindle horsepower defining the metal removal rate, chatter becomes the limiting factor that keeps the process from reaching its potential.

Problem 3: Cutting fluid or coolant issues.

Many small manufacturers serve a number of customers who demand short production runs and fast turnaround times. These so-called “job shops” must change their machine tool set-ups and cutting or coolant fluids to fit the work, and these quick changes can cause unforeseen problems.

Polarity-shifting or pH-shifting reactions between your cutting fluid and residual fluid from a previous job, or a slow build-up of water hardness within the system, could leave your shop’s high-value metal stock susceptible to corrosion. Some estimates peg US manufacturers’ annual losses from corrosion at close to $300 million.

Chemical foaming, caused by interactions between the new fluid and the previous production run’s fluid residue, or by reactions between the fluid concentrate and dissolved minerals within the water used to dilute it, can reduce a cutting fluid’s efficiency and lead to defective machining or premature tool wear.

Mechanical foaming might be caused by a low fluid level in the tank, which in turn causes air to mix into the fluid during the course of normal operation. It can also be caused by small leaks in the pump housing or intake lines, by fluid velocities being set too high, by excessive agitation, or other machine-based factors.

What you can do about it:

You can conduct a cast-iron chip (CIC) test to see how much protection your cutting fluid is providing. We supply two types.

ASTM International recognizes TechSolve’s ASTM Designation Cast Iron Chips D4627-12 as the material of choice for conducting the standard test for iron chip corrosion in water-dilutable metalworking fluids. They’re produced and certified in accordance with industry requirements and procedures, as defined by ASTM Grey Iron Class 30.

Our IP287 Cast Iron Chips are made per the Energy Institute’s guidelines, using the same tools and techniques that Machining Research incorporated used to produce them prior to our acquisition of that group in 2014.

If your CIC test reveals a problem that you’re unable to identify, we can likewise help you with cutting / coolant fluid analysis, manufacturing process troubleshooting, and materials consulting.

Problem 4: Set-up / downtime bottleneck

Maybe it’s that dinosaur machine in the corner that’s always experiencing a feeder jam. Maybe it’s the low-RPM, precision job near the bottom of your throughput cycle that takes a long time to complete and becomes a limiting factor on production.

Or it could be the time your operators have to spend cleaning machines, changing out fluids, tools, and stock for shorter production runs.

Pre-Industry 4.0, minor delays on the line might have gone unnoticed and become an accepted matter of course.  Minutes-long downtimes could easily add up to hours-long (even days-long) inefficiencies in the manufacturing process.

Today, they don’t have to. IIoT technologies allow small and mid-sized manufacturers to identify the bottlenecks that slow their throughput and cost them so dearly.

What you can do about it:

Connect your machines. It’s easier and more affordable than you might think.

Even that legacy machine can be adapted  — with the addition of an off-the-shelf DAQ unit, a computer and a bit of software — to report back to you, reveal its hidden inefficiencies and show you what you need to work around.

Problem 5: Human limitation

Robots and automation aren’t phasing human workers out of manufacturing. After all, someone needs to be there to do the innovating, the problem-solving, the machine maintenance and the process optimization.

But human beings nevertheless do have limitations. And, sometimes, those limitations might impact productivity on the line.

An operator may have difficulty lifting or loading stock onto a machine and, over the course of the shift, tire to the point that the line’s overall throughput becomes limited.

A junior operator might be unsure in a particular skill needed to complete the job to which he or she is assigned, and need more time to complete that task than another, more experienced worker on the floor might need.

What you can do about it:

Again, data from your machines will greatly aid your cause here. Digital connectivity will help you identify human-based inefficiencies on the line.

That might sound unsettling to production floor staff who are averse to having their work scrutinized, so it’s important to approach monitoring from a positive, professional development mindset, and to clearly communicate that to your staff to achieve buy-in.

Show them that the reason for monitoring their productivity on the line isn’t to single out and remove weak links in the company’s workforce. Rather, you’re identifying opportunities for mentoring, additional training, upskilling, or even cobot assistance, that might help each person succeed and grow his or her role within your company.

Once you have data flowing and showing you the slowdowns in your production efficiency, we can likewise help your company develop easier workflows, more efficient manufacturing processes and robust professional development programs, so you can help the whole team to rise to the Industry 4.0 challenges you collectively face.

In manufacturing, it’s all about the details. We can help you uncover them.

If you’re curious about what you can do to improve your shop’s machining efficiency and move your manufacturing operations forward, our TechSolve team can speed up your discovery process.

From problem diagnosis and machinability testing, to growth strategy development and new business opportunity identification, we’re uniquely positioned to help your business stay apace of Industry 4.0.

Click here to contact us. We’re eager to listen to your business challenges and solve them with you.