cost per cut
May 30, 2016 / best practices, blade failure, blade life, bottlenecks, continuous improvement, Cost Management, cost per cut, LIT, operator training, preventative maintenance, root cause analysis
For any metal-cutting operation, bottlenecks are the enemy. Whether caused by machine error, tooling failure, user error, or some other maintenance issue, the end result is typically the same—increased downtime, rework, and scrap, all of which eat into the bottom line. And for a high-production operation like ball and roller bearing manufacturing, a hiccup in early sawing operations can quickly wreak havoc on the entire production process and schedule.
Although circular sawing may seem like a simple operation, there are number of variables that play a role in achieving consistent, quality cuts while also getting the most out of each saw blade. As an archived article from Fabricating & Metalworking explains, “Saws are very much like the people who use them: they don’t react well to heat, shock, abrasion, stress, and tension.” Far too often, managers and operators ignore these critical factors and, as a result, experience premature blade failure and end up going through far more blades than necessary.
Proper cutting speeds, feed rates, blade tension, and lubrication all tie into blade life—a factor any blade buyer knows is critical when it comes to cost.
“Precision circular saw blades can be upwards of $200 a piece, so you don’t want to just go through those,” Mike Baron, vice president of Jett Cutting, says in a case study published by the LENOX Institute of Technology (LIT). “If I am getting 100 pieces an hour at this setting, but push it up to get 150, I may be going through twice as many blades. It just isn’t cost effective.”
Glen Sliwa, maintenance manager at metal service center A.M. Castle & Co, also focuses on blade life to better manage costs. In addition to following a strict preventative maintenance program to save on tooling and equipment costs, Sliwa says it is just as critical to ensure operators know how to optimize blade life. This includes training operators to follow manufacturer suggested cutting parameters, as well as closely tracking tolerance requirements so blades can be reused whenever possible.
“We’re looking at how many pieces that we can get off that blade and then stand perpendicular to the part,” Sliwa explains. “If you have to stay within ten-thousandths or five-thousandths on the cut, and that blade is no good, I can take it off that machine and put it on another one and I can cut an eighth of an inch, 125 thousandths. So I’m still getting more blade life out of it, but it’s not interfering with that customer’s specifications.”
To help ball and roller bearing manufacturers extend the life of their circular saw blades, the below chart offers a few troubleshooting tips from LIT’s reference guide, “Tips and Tricks to Optimize Your Precision Circular Sawing Operation.” By understanding some common blade issues and their root causes, operators can reduce premature blade failure and, in turn, improve your operation’s overall productivity and save on tooling costs.
For more downloadable information on optimizing your company’s precision circular sawing operation, you can visit LIT’s resource page here.
cost per cut
May 10, 2016 / best practices, Cost Management, cost per cut, KPIs, lean manufacturing, operations metrics, optimization, predictive management, productivity, ROI, workflow process
As fabricators continue to seek new ways to optimize their operations, many are turning to software. Whether using it to connect the plant floor to the front office, or to measure key performance indicators (KPIs), data shows that more and more fabricators view software as a smart—and necessary—manufacturing tool.
For example, according the “2016 Capital Spending Forecast” from the Fabricators & Manufacturers Association International, more than 94 percent of survey respondents said their software spending this year would either remain the same or increase. This is significant, especially as more and more reports show that many companies are pulling back on spending this year.
A separate benchmarking survey from Modern Machine Shop shows that leading shops are more likely to utilize advanced software programs in their operations. Specifically, the survey found that top-performing machine shops (referred to as “top shops”) are more apt to utilize software solutions like enterprise resource planning (ERP) and toolpath simulation software in comparison to other shops.
While there are many reasons software is becoming a valuable tool for manufacturers, for fabricators, a lot of it has to do with evolving customer demands. “As more custom fabricators are taking on more design work—beyond just design for manufacturability—engineering and estimating functions become more complex, especially as that work focuses on more subassemblies and full assemblies that call for multilevel bills of material and a multitude of sourced parts,” states a report from thefabricator.com. This, the article continues, is causing shops to invest in better methods of communication, as well as software tools like CAD/CAM, nesting systems, and ERP.
The good news is that as more manufacturers embrace software, the more tools are being developed—both by software designers and supply chain partners. Like consumers, industrial manufacturers are finding that where there is a need or challenge, there is indeed “an app for that.”
In metal cutting, specifically, there are several tools fabricators can use to help optimize their operations—many of which are free of charge. Below are two in particular that fabricators may find helpful:
- Bandsawing. SawCalc, a web-based software program from LENOX, is a free online tool that helps plant managers and operators solve band-sawing challenges encountered in the field by providing cutting recommendations for maximum blade performance. Users have free access to the program, which determines the proper cutting parameters based on material composition, size and shape, as well as the machine model. The program’s library of materials is regularly updated, providing accurate cutting recommendations for 54 country standards, and more than 35,000 materials and 9,000 band saw machines. Because the program is web-based, managers and operators can access the service right from the shop floor. Aerodye Alloys, a service center featured here in a case study, says that using the online tool has helped increase efficiency at one of its facilities by about 15 to 20 percent.
- Circular Sawing. For fabricators using circular saws, Tsune America has developed Sawculator, a free web-based software tool to assist fabricators and other industrial metal-cutting companies with pre-planning their sawing requirements. The downloadable program allows users to perform automatic US and Metric Dimensional Conversions on the fly, makes automatic suggestions for proper blade selection and chip load, provides more than twenty cutting job outlines, and calculates everything from estimated blade life and bar utilization to trim cut and net cutting time. Users can report prospective cutting jobs to their computer screen, as well as send it to concerned participants on the job via a local printer, email or Smart phone outputs. You can view a video of how the program works here.
Enhance Your Toolbox
Having the right tool for the job has always been a critical part of any metal-cutting operation, but fabricators are finding that it pays to have more than just hardware in their strategic toolbox. While it will never replace the important work machinery and other hardware tools perform on the shop floor, software tools can further optimize cutting operations by measuring important metrics, analyzing job trends, automating certain functions, and educating operators on proper cutting parameters. Although some software programs can be costly in terms of both money and training time, there are plenty of free tools available that can help even the smallest fabrication shop improve their operations.
What software tools are helping your shop optimize operations?
cost per cut
March 5, 2016 / best practices, blade life, blade selection, continuous improvement, cost per cut, LIT, operations metrics, operator training, ROI, strategic planning
For any manufacturing company, cost reduction has always been—and will likely always be—a top priority. However, like many other business strategies, managers are starting to look at cost management holistically. Instead of simply looking at price tags and cost reduction, today’s managers are looking at long-term return on investment and optimization.
This type of “holistic” approach to cost management is being adopted by several large manufacturers, including food giant General Mills, but it can also be applied on the shop floor of any industrial metal-cutting operation. One specific way metal service centers can apply this concept is by measuring “cost per cut.”
Instead of simply looking at the cost of a blade or even how many cuts a blade performs, “cost per cut” measures the total cost it takes for a shop to perform a cut, including raw material, blade, machine and operator costs. This metric gives service centers a better indication of overall production profitability.
A good analysis of cost per cut should include the following:
- total cuts per blade
- expected blade life
- the number of cuts required for the finished good
- labor and training costs
- utility and other overheard costs to truly optimize cutting operations
Of course, the question for many companies is not how to measure cost per cut, but rather, how they can reduce their cost per cut. Tools like the spreadsheet calculator, “ROI Analysis of Making Improvements to Cost Per Cut,” can be helpful in making that determination. The tool takes into consideration all equipment and factors beyond mechanics that can improve cost per cut rates and a shop’s bottom line.
Another optimization tool, SAWCALC, may also be helpful. The free, web-based software program recommends the correct band saw blade and sawing parameters based on material composition, size, shape and machine model, feed speed, as well as blade and tooth specifications that can streamline sawing processes and extend blade life.
One practical way service centers can reduce cost per cut is to consider investing in a coated saw blade. According to an article from Canadian Industrial Machinery, coating can extend blade life by 100 percent or more and slice cutting time in half, depending on the blade material, coating, and the material being cut.
Although coatings can add a premium of 30 to 50 percent to the cost of a blade, there are instances when the upfront cost can pay off. “You need a reason like a challenging material, a need for extra performance, or a machine that is creating a bottleneck and needs to produce more parts,” Daniel Fernandes, brand manager for band saw blades at LENOX, explains in the CIM article. “Upgrade to a coated blade and you can pump more jobs through the same equipment. You’ll get more out of your overhead costs and your labor.”
Another service center, featured here in a case study, was able to improve its cost per cut by re-adjusting its sawing parameters, increasing its operator training, and upgrading some of its blades. In one instance, the service center was able to reduce cut time by 40 percent.
Is a new, upgraded blade always the answer? Of course not, but optimization should always be the goal. This is why metrics like cost per cut are so important. By focusing more on reducing the true cost of each cut—and not just the price tag of a blade—managers can optimize their metal-cutting operations and, hopefully, see the results in the bottom line.
How has your service center improved cost per cut? What tools have helped you optimize your operations?
cost per cut
January 25, 2016 / best practices, blade failure, blade life, blade selection, bottlenecks, cost per cut, operator training, preventative maintenance, productivity, quality, root cause analysis, workflow process
For any metal-cutting operation, blade life is critical. Premature blade failure not only results in increased tooling costs, it can also increase downtime, rework, and scrap—all of which eat into the bottom line.
For forges that cut and process metal, however, blade life is even more crucial. The scale that forms on forged metal pieces can quickly deteriorate blade life, which makes blade selection extremely important. In most cases, forges require aggressive bandsaw blades with varied tooth geometries that can get underneath any scale buildup (i.e., carbide-tipped blades).
While choosing the right blade is a good start, blade life also relies on a variety of other variables, including proper cutting speeds, feed rates, blade tension, lubrication, and break-in procedures. As an article form Fabricating & Metalworking explains, “Saws are very much like the people who use them: they don’t react well to heat, shock, abrasion, stress, and tension.” Far too often, managers and operators ignore these critical factors and, as a result, experience premature blade failure and end up going through far more blades than necessary.
To help forges extend the life of their band saw blades, below are a few troubleshooting tips from the reference guide, “User Error or Machine Error?”, from the LENOX Institute of Technology. By understanding some common blade issues and their root causes, operators can reduce and, hopefully, eliminate premature blade failure.
Issue #1: Heavy Even Wear On Tips and Corners Of Teeth
The wear on teeth is smooth across the tips and the corners of set teeth have become rounded.
- Improper break-in procedure
- Excessive band speed for the type of material being cut. This generates a high tooth tip temperature resulting in accelerated tooth wear.
- Low feed rate causes teeth to rub instead of penetrate. This is most common on work hardened materials such as stainless and tool steels.
- Hard materials being cut such as “Flame Cut Edge” or abrasive materials such as ” Fiber Reinforced Composites”
- Insufficient sawing fluid due to inadequate supply, improper ratio, and/or improper application
Issue #2: Wear On Both Sides Of Teeth
The side of teeth on both sides of band have heavy wear markings.
- Broken, worn or missing back-up guides allowing teeth to contact side guides
- Improper side guides for band width
- Backing the band out of an incomplete cut
Issue #3: Wear On One Side Of Teeth
Only one side of teeth has heavy wear markings.
- Worn wheel flange, allowing side of teeth to contact wheel surface or improper tracking on flangeless wheel
- Loose or improperly positioned side guides
- Blade not perpendicular to cut
- Blade rubbing against cut surface on return stroke of machine head
- The teeth rubbing against a part of the machine such as chip brush assembly, guards, etc.
Issue #4: Chipped Or Broken Teeth
A scattered type of tooth breakage on tips and corners of the teeth.
- Improper break-in procedure
- Improper blade selection for application
- Handling damage due to improper opening of folded band
- Improper positioning or clamping of material
- Excessive feed rate or feed pressure
- Hitting hard spots or hard scale in material
Issue #5: Body Breakage Or Cracks From Back Edge
The fracture originates from the back edge of band. The origin of the fracture is indicated by a flat area on the fracture surface.
- Excessive back-up guide “preload” will cause back edge to work harden which results in cracking
- Excessive feed rate
- Improper band tracking – back edge rubbing heavy on wheel flange
- Worn or defective back-up guides
- Improper band tension
- Notches in back edge from handling damage
cost per cut
December 5, 2015 / blade life, blade selection, Cost Management, cost per cut, LIT, material costs, optimization
Any metal-cutting expert knows that having the right blade for the job is critical. Although it may seem like a small operational detail, blade performance impacts several key business areas, including productivity, maintenance, quality, and tooling costs.
Like any purchasing decision, blade selection needs to be strategic, taking into consideration a host of variables—business goals, material type, equipment, and operator skill level, to name just a few. Blade performance is also based on several variables—the cutting application, blade specification, number of teeth per inch, tooth set, etc. Put simply, not every blade is created equal, and choosing the wrong blade can result in poor quality cutting and higher operational costs.
The problem is that many of today’s service centers don’t even realize they are using the “wrong” blade. In many cases, companies settle for “good” instead of “great.” Managers and operators become content with the blade technology they’ve been using for years and end up missing out on the benefits a new blade technology could bring to their operation.
This is a common occurrence in band sawing. For example, many service centers have used bi-metal band saw blades over the years and have had decent results. And in many cases, bi-metal blades are a good choice. However, there are applications in which carbide blade technology would be the better choice.
Many companies are finding that making the switch to carbide blade technology can provide savings and productivity gains they would never have achieved with bi-metal blades. This was the case for Aerodyne Alloys, a metal service center featured here in Today’s Energy Solutions. For years, the company’s Greenville, South Carolina facility used bi-metal blades to cut its toughest metals, including stainless steel, nickel alloy, and super-alloys like Inconel 718 and Hastelloy.
To gain more performance out of its band saws, Aerodyne decided to upgrade to carbide blades. Carbide-tipped band saw blades use strong, durable materials to provide high performance, faster cutting, and prolonged blade life. The blade tooth has carbide tips welded to a high-strength alloy backing, allowing the metal service center to take on hard, nickel-based alloys, as well as stainless steel, tool steel, and titanium.
In addition to tackling hard-to-cut metals, carbide-tipped band saw blades offer longer blade life and faster cutting. The white paper, Characteristics of a Carbide-Friendly Band Saw Machine, further elaborates the benefits of the carbide technology by providing a real-life comparison between a bi-metal blade and a carbide-tipped blade. The test produced the following results:
- The bi-metal band saw blade (LENOX Contestor GT) ran 120 feet per minute with a feed rate of 0.53 inches per minute.
- The carbide blade (LENOX Armor CT Black) ran at 320 fpm with a feed rate of 3.11 inches per minute.
Ultimately, the higher speed and feed rate of the carbide blade enabled it to make the cut 13 minutes faster, translating into 160 more parts produced during an 8-hour shift than its bi-metal counterpart.
Carbide-tipped band saw blades can also deliver benefits to a metalworking operation by producing an improved surface finish. In many cases, a cut part will require additional processing steps downstream in order to refine the finish. By having a smoother finish, the carbide blade can reduce the number of secondary processes, which saves both time and money.
A good example of this is LENOX’s new carbide blade technology, which was featured in the latest issue of Modern Metals. Developed to cut aluminum and nonferrous alloys, the carbide-tipped band saw blade is able to make straight cuts at high speeds without sacrificing surface finish. As stated in the article, the blade tip’s particular grade of carbide wears very slowly, which is ideal for cutting aluminum. A multi-chip tooth pattern balances the chip load and reduces cutting forces, and sharp-edged teeth and high rake angles penetrate material more easily. The cutting tool is said to be the latest blade designed specifically to cut aluminum and nonferrous parts often used in today’s aerospace and automotive applications.
As carbide blade technology continues to advance, the more options service centers have to optimize and grow their operations. Whether the goal is to take on a harder material, improve performance, or increase quality, carbide-tipped blades are an investment worth considering. While the upfront product cost may be higher than other blade types, benefits like improved productivity, lower operational costs, and higher customer satisfaction will pay off in the long run.
For more information on the benefits of carbide blade technology, click here to download the white paper, “Leveraging Carbide Blade Technology to Increase the Productivity of Your Sawing Operation.”
cost per cut
August 30, 2015 / best practices, blade failure, blade selection, circular sawing, Cost Management, cost per cut, LIT, operator training, preventative maintenance, productivity, quality, root cause analysis
Like most high-production operations, ball and roller bearing manufacturers are running on tight schedules and can’t afford unexpected downtime or tooling issues. This means that every step of the manufacturing process must be optimized, starting with the first operation—circular sawing.
While precision circular sawing may seem like a simple operation, any metal-cutting expert can confirm that proper cutting depends on several variables. As this article from Canadian Metalworking points out, the overall performance of your cutting tool depends on speed, feed, depth of cut, and the material being cut. Knowing how to balance these variables is critical to cutting success.
For example, according to the white paper, The Top Five Operating Challenges Ball and Roller Bearing Manufacturers Face in Industrial Metal-Cutting, increasing the speed of a saw to get more cuts per minute without considering the feed setting or the demands of the material will result in premature blade failure and increased tooling costs. This, in turn, can lead to unplanned downtime for blade change-out, which directly impacts productivity.
Understanding how these different variables affect the cutting process can also help operators quickly and properly resolve any cutting challenges that arise. In many cases, this knowledge can make or break a production schedule.
To help ball and roller bearing manufacturers keep their circular sawing operations running at optimal levels, the LENOX Institute of Technology offers the followings tips for solving six of the most common problems operators may face:
Problem #1: Excessive vibration or noise
- Increase the feed rate
- Reduce the cutting speed
- Increase the lubrication
Problem #2: Crooked cutting
- The tooth pitch is too fine. Choose a coarser tooth pitch (e.g., change from 80T to 60T)
- Reduce the feed rate
- Evaluate the machine components (e.g., check the guides)
Problem #3: Wavy cutting
- Increase the feed rate
Problem #4: Chips are too hot or glowing
- Reduce the feed rate
- Reduce the cutting speed
- Increase the lubrication
Problem #5: Poor finish/Excessive stripping
- Reduce the feed rate
- Increase the cutting speed
- Change to a blade with a finer tooth count (e.g., 60T to 80T)
- Replace the blade
- Check the chip brush. Make sure it is fully engaged.
- Increase the lubrication
Problem #6: Heavy burr
- Reduce the feed rate
- Increase the cutting speed
- Inspect the machine components
- Replace the blade
For more information on optimizing your precision circular sawing operation, including best practices, white papers, and case studies, check out LIT’s resource center here.
cost per cut
August 10, 2015 / best practices, blade failure, blade life, blade selection, cost per cut, industry news, LIT, preventative maintenance, productivity
As reported in our recent Metal-Cutting Industry Report on Non-Residential Construction, the use of industrial and structural steel tube and pipe is growing. According to a market tracker from Metal Bulletin Research (MBR), the category is growing at the fastest rate since the recession, mostly due to economic growth and falling oil prices.
“Construction demand for structural tubing is now growing at a steady pace in most regions of the USA,” the MBR report states. “There has been some concern among market participants that the drop in oil prices and the associated hit to the local energy-centered economies would be detrimental to their construction outlook, especially since these were some of the initial drivers of growth in the recovery. So far, construction continues unabated, as contracts, financing and permitting have already been settled.”
Industry players are also optimistic. HGG, a supplier of tube-processing machinery, told MetalForming magazine it expects the category to grow by about 15 percent in North America alone. (You can read the full MetalForming article here.)
This is good news for fabricators that serve the industrial and commercial construction industries or that cut structural tube for other applications. In either case, most shops are working with hollow structural steel (HSS) tube specified to ASTM A500 (the standard specification for cold-formed welded and seamless carbon steel structural tubing in round, square and rectangular shapes). Although most shops wouldn’t categorize HSS as difficult to cut, it does have some unique characteristics operators need to understand to ensure proper cutting.
Unlike solid tubing, which only requires one cut, HSS tube requires the blade to cut through two thin solids with a space in between. These types of cuts—known as interrupted cuts—are best suited for bi-metal band saw blades because they are designed to withstand the vibration. Carbide band saw blades, on the other hand, have strong, durable teeth, but they are not shock resistant. Therefore, bi-metal blades that reduce harmonics are the best choice.
HSS tubes also aren’t ideal for bundle cutting. While cutting tubing in bundles can allow shops to increase the number of parts per shift, it can substantially reduce blade life. In fact, some experts say that any increased part volume efficiency is offset by a 20 to 25 percent reduction in band life.
A recent article from thefabricator.com highlights several other best practices for sawing structural tube. The following are a few of the industry publication’s tips:
- Look for variable clamping pressure. This allows for the vise-clamping pressure to be reduced to prevent deformation of thin-wall tube. The pressure should be enough to hold the tube firmly to ensure it doesn’t move, but not enough to bend it.
- Watch for the weld orientation. Although quality saws will cut a tube regardless of the weld orientation, a fabricator should position the weld at the top or side of the saw entrance, rather than at the bottom, to maximize tool life. (Note: In a bottom-up cutting configuration, the weld should be at the bottom or on the side.)
- Be aware of blade bias. When cutting non-round tubing in a band saw, it is preferable to have a bias on the blade (ie, a canted head). This is valuable for both good cut quality and longer blade life. Having the blade penetrate the material at an angle allows the fabricator to use the most efficient tooth configuration and prevents overloading of the blade gullet. Even a 1- to 3-degree bias will do the trick; a very large bias, however, will add to the overall cut time.
- Pay attention to tooth geometry. Using the correct tooth geometry for a particular application helps to ensure a quality cut, while also prolonging the blade life. Although it is possible to use one type of blade for most structural tube applications, fine-tuning it for longer production runs is worth the additional effort. As a general rule, a fabricator using a band saw wants six to 12 teeth to be exposed to the widest part of the cut.
For more guidelines on cutting HSS tube, including a discussion on circular saw blade options, you can read the full thefabricator.com article here.
cost per cut
August 5, 2015 / best practices, blade failure, blade life, blade selection, cost per cut, industry news, material costs, preventative maintenance, productivity, quality
Over the next few years, experts anticipate growth in the use of high performance alloys or “superalloy” materials such as Inconel and Hastelloy. The high-performance metals, which are known for their outstanding corrosion and high temperature resistance, continue to find uses in aerospace and aircraft applications, and more recently, are expanding into the oil and gas industries.
“Growing corrosion as a cost concern in exploration and production in offshore drilling rigs is expected to propel use of high performance alloys such as superalloys in oil and gas applications,” states one study from Grand View Research, Inc. “Non-ferrous alloys such as nickel and titanium are also expected to witness above average growth due to their high mechanical strength coupled with increased use in aerospace, oil & gas and gas turbine applications,” the study continues. Specifically, Grand View Research forecasts that superalloy demand will experience an annual compound growth rate of more than 3.0 percent from 2014 to 2020.
While there is certainly a science to cutting any metal material, tackling tough-to-cut materials like superalloys can be even more challenging as managers try to balance cutting speed, finish quality, and blade life. However, with the right tools and know-how, service centers can efficiently and cost-effectively handle tough-to-cut materials without compromising quality.
The following are three key tips for service centers that want to cut superalloy materials:
- Use the right blade. Although it is possible to use bi-metal band saw blades to cut superalloys, carbide-tipped blades are typically better suited for the task and offer longer life, faster cutting, and better part finish. As with bi-metal blades, carbide-tipped blades are designed with multi-metal tooth constructions to provide high performance and prolonged blade life. In a carbide blade, the more durable tooth tips are welded to a high-strength alloy backing, enabling it to cut even the toughest metal. While carbide blades are more expensive, they are designed to take more bite and more chip load, which allows for faster cutting and can improve productivity and cost per cut. Aeordyne Alloys, a service center featured here in a LENOX case study, found this to be the case. Working with hard-to-cut metals like Inconel 718 and Hastelloy X, the service center decided to upgrade from bi-metal blades to carbide-tipped blades to get higher performance out of its band saws. By using a carbide blade, Aerodyne was able to tackle the hard, nickel-based alloys, while also improving cutting time on easier to cut materials like stainless steel.
- Coolant is key. There is no question that tougher metals take a toll on blade life, but this issue is even more compounded if operators fail to use coolants. As explained in an article from Canadian Industrial Machinery (CIM), choosing the right coolant, as well as getting the coolant into the cut, will extend blade life and improve cut quality. While some experts suggest highly compounded straight oil coolants for the more difficult tocut metals like superalloys and certain stainless steels, Matt Lacroix, director of marketing, LENOX Industrial Products & Services, says the choice isn’t always that simple. “There’s an inverse relationship between the lubrication and cooling effect of the fluid,” Lacroix tells CIM. “A water-soluble oil or straight oil is good for lubrication, but not as good for cooling. The synthetics and semisynthetics are better for cooling, but offer less lubricity than fluids with a higher oil content.” In the end, Lacroix says selecting the right coolant depends on the application.
- Break in blades. As discussed in a previous blog post, when it comes to band sawing, it always pays to break in blades. This is especially true when getting ready to cut harder materials that quickly wear down band saw blades. A new blade has razor sharp tooth tips, and in order to withstand the cutting pressures used in band sawing, tooth tips should be honed to form a micro-fine radius. Failure to perform this honing will cause microscopic damage to the tips of the teeth, resulting in reduced blade life and poor-quality cuts. When done correctly, performing this simple task can extend blade life by up to 30 percent.
cost per cut
July 30, 2015 / best practices, blade failure, blade life, Cost Management, cost per cut, LIT, preventative maintenance, resource allocation, ROI
As any machining expert will tell you, coolants are a critical part of the metal-cutting process. While they are an added cost and an added step in the production process, the long-term cost benefits of coolants are worth every dime and every minute spent. This is especially true if your goal is optimization. As an article from Production Machining states, manufacturers should view coolants as an asset or, better yet, a “liquid tool.”
Unfortunately, many managers and operators fail to understand the importance of proper lubrication during the metal-cutting process. According to Modern Machine Shop, most manufacturers see lubricant as “the least important factor in the total cost of machining and the last place to look for process improvements.” In fact, it is common for companies to often “cheat” on the proper concentration levels of metal-cutting fluids in order to save money. This may reduce coolant costs in the short term, but the high costs of machine wear and tooling replacement make this a poor management choice.
As explained in the white paper, Understanding the Cut: Factors that Affect the Cost of Cutting, coolants provide lubrication, which is essential for long blade life and economical cutting. Properly applied to the shear zone, lubricant substantially reduces heat and produces good chip flow up the face of the tooth. Without lubrication, excessive friction can produce heat; high enough to weld the chip to the tooth. This slows down the cutting action, requires more energy to shear the material, and can cause tooth chipping or stripping, which can destroy the blade.
Like any manufacturing tool, proper use and coolant management is essential if you want to get the most out of your investment. To help ball and roller bearing manufacturers ensure proper lubrication management in their metal-cutting operations, the LENOX Institute of Technology offers the following five tips:
- Start with a clean machine. As an article from MoldMaking Technology explains, proper metalworking fluid management starts with the draining, cleaning, and recharging of the machine. When changing coolants for any reason, clean and disinfect thoroughly with a fluid advised by the supplier of the coolant.
- A proper fluid mix is key. Extending the life of your fluids and achieving the best fluid performance starts with proper fluid preparation. Metal-cutting fluids need to be mixed a certain way in order for their chemical makeup to be correct. Experts recommend pouring the water into the mixing container first and then stirring the coolant concentrate into the water. One way to remember the proper technique is by the acronym O.I.L. (Oil In Last).
- Remove tramp oil to extend fluid life. Waste oils, which come from the machine or surfaces of the raw materials, are often picked up by the metalworking fluid and are referred to as “tramp oils.” Regular removal of tramp oil from the manufacturing process helps improve fluid performance and longevity, air quality, bacterial resistance, corrosion resistance, and tool life. Typical methods for tramp oil removal include regular inspection and the use of skimmers, centrifuges, and coalescers.
- Monitor fluids regularly. Measure, with a regular frequency, the concentration and quality of your fluids. Testing tools include refractometers, which can quickly determine the total amount of solubles in a solution, or titration kits, which are more extensive and are used to analyze fluid concentration in metal-cutting fluids contaminated with tramp oils. Tests for PH levels and alkalinity can also be useful, as pH readings outside the acceptable range indicate a need for machine cleaning, concentration adjustment, or the addition of biocide.
- Make coolant checks part of everyday maintenance. Instituting regular coolant checks as part of a preventative maintenance program or daily operator checks can eliminate unnecessary tooling costs and maintenance downtime. Low coolant levels on a band saw, for example, can lead to premature and uneven wear of band wheels, which typically cost $1,000 each.
While coolants may feel like just another cost item on your consumables list, they play an important role in keeping maintenance costs down and cutting tool performance high. By following a few best practices, ball and roller bearing manufacturers can ensure that their metal-cutting coolants are not a necessary evil, but an opportunity to improve process efficiencies.
cost per cut
July 10, 2015 / blade failure, blade life, blade selection, Cost Management, cost per cut, LIT, productivity, resource allocation, ROI
Most operations managers understand the importance of keeping productivity high and costs low. However, many managers fail to understand that in many cases, spending more in the short term is necessary to achieve the long-term goal of productivity.
This concept is especially true when it comes to metal-cutting tools. Because tools are consumables that need to be purchased and replaced often, it is tempting for managers to focus more on upfront cost. But as the following examples will explain, this strategy does not always offer the best return on investment.
At an event held earlier this year, Jacob Harpaz, CEO of Ingersoll Cutting Tools, explained why managers need to look beyond the price tag when investing in a new tool. According to Harpaz, featured here in Modern Machine Shop, a cutting tool can deliver improvement in three ways:
- Lower price
- Longer tool life
- Greater productivity
Although all three can be beneficial, Harpaz says choosing a tool with greater productivity will always offer the most lucrative return. Here’s why: For a representative machined part, Harpaz estimates that the cost of machinery represents 26 percent of the cost of machining a part; overhead represents 21 percent of the unit cost of machining; and labor and raw material account for 28 and 22 percent, respectively. Meanwhile, the cost of cutting tools accounts for just 3 percent.
The implications of this are significant, according to Harpaz. Using the above estimates, dropping the price of the tool by 20 percent would only deliver a 0.6-percent unit cost reduction. The seemingly even greater change of increasing the life of the tool by a factor of 2 would still only save 1.5 percent. However, increasing productivity would increase the number of pieces the shop can produce in the same period of time, which means the labor cost, overhead cost, and machinery cost per piece would all decrease. Increasing productivity by 20 percent, thus, produces a savings of 15 percent overall, providing the greatest savings opportunity.
Benefits of Upgrading
With the above in mind, managers that want to get the best return out of their tooling need to remain open about investing in upgrades and new technologies In saw blades, advancements in tooth geometry and wear-resistant materials are providing significant improvements for many metal-cutting operations. This article from Canadian Industrial Machinery, for example, explains why the additional cost of a coating on a band saw or circular saw blade can be worth the investment, especially when cutting a challenging material or when higher performance is needed.
There is no question that high-performance blades will cost more. However, because they are able to cut faster and with more accuracy, they improve productivity and save money in the long run. O’Neal Steel, a Birmingham, Alabama-based fabricator featured in a white paper from the LENOX Institute of Technology, found that incurring a significant upfront expense to upgrade some of its blade was worth it. Before the upgrade, O’Neal was spending about $90 per blade, but the fabricator was only getting one day’s worth of cutting. “We had a fair margin, but we were constantly messing up material,” explains Jim Davis, corporate operations services manager. “Most people think it’s costing a lot of money in blades to switch. Well, that’s true, but when you’re cutting really tight tolerances, your blade’s going bad and the material lengths are off, you can add up money really fast and lose all your profits in just an hour or two if you have blade issues.”
For another job in its Knoxville, TN, location, O’Neal was only getting two days of cutting per blade, so they were going through three blades a week. Again, Davis upgraded from a blade costing $280 to one that was $40 more, and immediately his blade-life increased to seven days.. He estimates that in the long run O’Neal saved $600 a week, or an annual total of around $30,000. “That’s a radical change, about a 3:1 ratio on the life of a blade,” said Davis.
The Deciding Factors
Of course, not every upgrade will be worth the cost. The key is for managers to weigh the opportunity cost against the hard cost, considering the true benefits a new tool can offer and whether or not it will contribute positively to the bottom line. To do this effectively, managers need to work closely with their tooling partners to discuss the pros and cons of the different metal-cutting options, while also evaluating all of the factors that contribute to the cost of the cutting process. If the long-term benefit is there, managers need to be sure they aren’t being shortsighted by the price tag. As fabricators like O’Neal are finding, the upfront investment may offer higher productivity, as well as substantial bottom-line savings.