Banner
Sawing/Cutting

Get sawing

By Russ Olexa

Faced with many different saws, how does a fabricator choose what's best for his operation?

When a bandsaw cuts a wafer-thin piece from steel-bar stock, and this piece has the same thickness all the way around its circumference, this says a lot about the capabilities of the saw.

In fact, this demonstrates that the saw has the necessary quality built into it to keep the blade rigid to eliminate any deflection that could cause the cut piece to have an irregular thickness or be out-of-square. It's just one thing to look for when purchasing a saw.

Starting out
Saws used by fabricators are available in a number of different sizes, capabilities and configurations. These include horizontal and vertical bandsaws, circular saws, powered hacksaws and cut-off saws. Even though shops use powered hacksaws and cut-off saws, they aren't the focus of this article. Each has its benefits and a place in the shop.

But what is the best saw for your operation? What about low-cost saws from Asia? Can these be a choice for a fabricator's operation?

These saws might work for the do-it-yourself hobbyist, but once someone goes beyond backyard fabricating, these saws aren't a good choice for production. Inexpensive saws abound, but they aren't necessarily inexpensive when you consider their overall use, because a low-cost saw often means poor quality and a very short service life. They can be hard on blades and require more service and repair, meaning more downtime and less production. Also, when they break, will the parts be readily available? For want of an inexpensive part, the saw could be holding up a very expensive operation.

Right saw, right application
To find the right saw for an operation, Werner Rankenhohn, executive vice president of Kasto Racine, says, "It's application, application, application that drives what's needed in the shop. For instance, circular saws are up to three times faster than a bandsaw. So should every shop buy a circular saw? No, because they are limited to roughly a 6-in. diameter part. Beyond a certain part size, the shop needs to look at either a vertical or horizontal bandsaw."

Kerf loss (the amount of material removed when making the cut) is larger with circular saws. So when sawing expensive materials, this additional material loss can add up quickly.

Other questions that a shop should be asking to find the right saw are: What material is being cut, and what is its chemical composition? What is the materials' size and shape? How many parts are being cut?

Pete Haas, sales manager of Haas Saw/Supply, says, "A company's production people need to narrow down a machine that is most appropriate for what they have identified for their material sizes and types and production output. There's going to be a variety of parts cut by almost every shop. However, is the job shop cutting 10 of this and 50 of that or maybe 150? Or are personnel doing high production cutting such as 3,000 of one part, then 7,000 of another? The production people will have to look at the part quantities. They'll want a saw that's going to be able to do it all. Also, they'll have to look at the material and material requirements, and what the end finish requirements are on the material. So this is a good starting point for selecting the right saw."

Other considerations include the saw's operating system--manual, semi-manual or fully automatic with numerical controls--cutting speeds, automation extras and how much power it has. For instance, does the saw's design use pneumatics or hydraulics or does it have an all-electric operation? Is a manual bandsaw needed or one that's fully automatic to get the highest production capability?

Cliff Dixon, sawing product manager at DoAll Sawing Products, says, "Bandsaws are among the most versatile machines available. Some have manual operation, others have semi-automatic operation where the head lifts automatically, and still others are fully automatic with CNC control that moves the head automatically and controls the vise operations and advances the stock into the cutting area where pre-programmed cutting speeds and feed rates from the CNC control are fed into the saw. There are also a variety of band sawing machines with tilting heads, swivel heads or swivel bases that are designed specifically for miter cutting. Prices vary accordingly, but the right saw can make a huge difference in production capability."

In the saw's design, another consideration is the type of gearbox and gear ratios it has along with horsepower requirements and voltage needs.

Haas says, "As to horsepower, it depends on the material that the customer is cutting and what their production requirements are. They're going to need more horsepower for cutting solid materials in large diameters than they will if they're cutting tubes or angle iron. Once they know the largest part they'll be cutting and its shape and composition, it will help them select the correct saw."

Surface speed
He adds, "I can't emphasize this enough, the absolute number one thing that people miss when they pick a saw, and what sawing machine manufacturers almost always miss, is identifying the material and making sure that the surface speed that the blade runs at is appropriate for what is being cut. In the last 13 years I've seen it so many times where customers have a sawing machine for cutting stainless or for cutting aluminum, which are on two different ends of the cutting spectrum, and they have the wrong surface speed to cut that material."

For instance, when material has a nickel composition, such as in stainless steels, too fast a blade speed will work harden the material at the point of cut, making it difficult for the blade's teeth to penetrate.

Most circular saws for the fabrication type industry have a two-speed gearbox. So they have a low and a high speed. In most cases the low speed is used for tougher alloys like stainless. The higher speed is used for low-carbon steels, lighter alloys, aluminum and brass. And 99 percent of the time when the customer purchases the machine and installs it, the operators always associate a faster speed with a faster cut. So they cut it on the high speed and they don't ever turn the high speed off. The buyer is never advised that they really need to run at low speeds on difficult materials."

According to Dixon, bandsaws, however, usually have adjustable band speeds ranging anywhere from 60 fpm to 400 fpm or more. This allows the band speed to be precisely regulated to maximize cutting rates on a variety of different materials.

Saw automation
As with any equipment, quality components and construction are very important to achieve production levels. Components that should be factored in are the gearbox and the drive-motor's horsepower.

As to bandsaw components, Dixon says, "Look for high-precision band wheels for the blade. (DoAll's are cast iron with precision bearings.) Also, coolant should be on both sides of the blade, not just one. If it's only on one side, this can create heat on the opposite side and dull the blade, causing it to wander and lose its trueness."

Saw quality
Pat Mooney, president of Pat Mooney Inc., remarks that the saw's blade-guide system is a very important component for getting a proper cut. He says, "You want to have a minimum of a 1-in.-width saw blade. Anyone who tries to cut something with a 3/4-in. blade is just not going to cut very square, maybe on a really small part, but not as parts get larger. Also, you've got to have a good blade-guide and tension system so the blade is properly tensioned. Look further at the guide system. Is it a system that doesn't require a lot of adjustments? It should have fixed set positions where the blade slides into it. If the guides have to be adjusted every time the blade is changed, the operator isn't going to do it, and now you're not going to cut square. When you cut a part square, it improves the next process.

"Also, you want to look at the drive system," he says. "So the saw blade is efficiently driven. We use a direct-gear drive mechanism, where many other companies either use an angle drive or belts and pulleys."

Mooney also mentions that a flood coolant system is better to have than just a misting one or a direct application system when cutting solids. "Some of the spray systems work fairly well--not as good as the flood system--but they are adequate," he says.

"I would underspend on this feature, because the fluid you're going to disperse is pretty expensive," Mooney notes. "So you want to make sure it gets dispensed economically. For instance, on spray systems you're going to use a fluid that's going to cost perhaps $40 or $50 per gallon, and you want to make sure that you're only using a drop rather than a teaspoonful."

Dixon adds, "However, if you are cutting tubing, structurals or bundling the stock, misting may be the best solution. Flood coolants can flow through and around material and away from the cutting, thus reducing their effectiveness. Direct application fluids place just the right amount of coolant precisely where it's needed."

Lyle Menke, vice president of marketing at Peddinghaus Saws, says that a bandsaw needs to be a durable and very rugged machine. A shop owner also needs to think about buying a machine that's going to suit him five years down the road, because most saws will still be working 15 or 20 years from the purchase date.

He says, "Look for features such as efficient electronic technology. For example, we use a touch-screen control unit on smaller saws that will handle up to a 16-in.-by-16-in. capacity. They have a touch screen that allows the operator to input 90-degree cuts, 45 left, 45 right, 62 degrees left, 62 degrees right and be able to optimize parts.

"Think about the future," Menke says. "If you buy this machine now, is it going to satisfy what I'm running now? Will it help me to grow my business?" He says that if a small shop never gets into CNC or NC saws, they should get a machine that's not just cost-efficient, but that's durable, because time is money. Get a machine that has parts readily available from the manufacturer that stands behind the product. The saw should come with a comprehensive manual, so if a problem arises it can be diagnosed.

Circular saws
Haas says that circular saws are usually less expensive than a bandsaw. An advantage of a circular saw is that the saw blade can be re-sharpened and not just thrown away, but they are up to three times more expensive. However, he says that a negative for this type of equipment would usually be material capacity and versatility.

"Bandsaws usually give you much more capacity in terms of cutting and size," he adds. "They also give you more versatility. So you can cut perhaps an 8-in. solid bar and then throw a small piece of angle iron in it. Whereas, a circular saw is limited by the diameter of the blade and its capacity. So generally there is a much narrower window of cutting capacity."

The correct saw
Haas mentions, "By answering all the questions in this article, it should help you narrow down your choices to probably one or two different types of saws that will work for you. Now it becomes a matter of what the cost of this cutting is versus using a different cutting method. What is the cost of a saw versus a competitor's saw of a similar size and type? What are the maintenance costs? Are there any spare parts that are required? If the saw breaks, you'll want to know what it's going to cost to have someone fix it, or whether you can fix it yourself. What is the warranty on the saw? What type of payment terms are offered from the saw manufacturer? How are they going to work with me and what's the delivery time? Once you answer these, you should know what to buy." FFJ

Company Profiles

AIR FILTRATION

IRONWORKERS

NESTING SOFTWARE

SERVICE CENTERS

Camfil APC - Equipment Trilogy Machinery Inc. Metamation Inc. Admiral Steel
Camfil APC - Replacement Filters

LASER TECHNOLOGY

PLASMA TECHNOLOGY

Alliance Steel
Donaldson Company Inc. AMADA AMERICA, INC. Messer Cutting Systems Inc.

SOFTWARE

BENDING/FOLDING

Mazak Optonics Corp.

PLATE

Enmark Systems Inc.
MetalForming Inc. MC Machinery Systems Inc. Peddinghaus Lantek Systems Inc.
RAS Systems LLC Murata Machinery, USA, Inc.

PLATE & ANGLE ROLLS

SecturaSOFT

BEVELING

TRUMPF Inc. Davi Inc. SigmaTEK Systems LLC
Steelmax Tools LLC

LINEAR POSITION SENSORS

Trilogy Machinery Inc. Striker Systems

COIL PROCESSING

MTS Sensors

PRESS BRAKE TOOLING

STAMPING/PRESSES

Bradbury Group

MATERIAL HANDLING

Mate Precision Tooling AIDA-America Corp.
Burghardt + Schmidt Group EMH Crane Rolleri USA Nidec Press & Automation
Butech Bliss Fehr Warehouse Solutions Inc.

PRESS BRAKES

STEEL

Red Bud Industries UFP Industrial AMADA AMERICA, INC. Alliance Steel
Tishken

MEASUREMENT & QUALITY CONTROL

Automec Inc.

TUBE & PIPE

CONVEYOR SYSTEMS

Advanced Gauging Technologies MC Machinery Systems Inc. BLM Group
Mayfran International

METAL FABRICATION MACHINERY

SafanDarley HGG Profiling Equipment Inc.

DEBURRING/FINISHING

Cincinnati Inc.

PUNCHING

Prudential Stainless & Alloys
ATI Industrial Automation LVD Strippit Hougen Manufacturing

WATERJET

Lissmac Corp. Scotchman Industries Inc.

SAWING

Barton International
Osborn Trilogy Machinery Inc. Behringer Saws Inc. Jet Edge Waterjet Systems
SuperMax Tools

METAL FORMING

Cosen Saws Omax Corp.
Timesavers FAGOR Arrasate USA Inc. DoALL Sawing

WELDING

HYDRAULIC PRESSES

MetalForming Inc. HE&M Saw American Weldquip
Beckwood Press Co.

MICROFINISHING TOOLS

Savage Saws Strong Hand Tools
Triform Titan Tool Supply Inc.

 

T. J. Snow Company

TPMG2022 Brands


BPA_WW_MASTER.jpg