Above: A 20 in. aluminum cutting saw blade loaded on the Vollmer CHD270 grinding center for re-sharpening.
Different metals require different tooth configurations and getting it right saves money
March 2013 - The type and thickness of metal being cut often determine blade life. “Copper cuts differently than any other metal out there so we have to make sure we have a configuration setup that works,” says Tom Horner, machining operations manager at IBC Advanced Alloys, Copper Alloys Division, Franklin, Ind.
The company, headquartered in Vancouver, British Columbia, supplies copper for the aerospace, oil field, automotive, electronics and welding industries. IBC manufactures and distributes a wide array of copper alloys as castings and forgings in plate, block, bar and rings, as well as specialty copper alloy forgings for plastic mold tooling and resistance welding applications.
“Most of the time we’re shipping plate that is sawed many more times by our customers,” Horner says. “We saw up to 3 ft. by 8 ft. long pieces in various thicknesses and we ship to customers all over the world.” IBC’s customers then cut that material to specific sizes as needed.
While metals such as steel have relatively stable prices that may vary from month to month, copper and copper alloy pricing is quite volatile, often fluctuating daily. Mistakes can be costly to IBC as the company needs to complete jobs accurately and in a timely fashion to avoid losing revenue.
To help keep costs in check, IBC turns to Phillips Saw & Tool Inc., Frankfort, Ind., for carbide-tipped plate saw blades, as well as its repair and sharpening needs.
Spindle speed
IBC uses Phillips’ saw blades to cut copper alloys from 3⁄4 in. thick to 6 in. thick. Blades wear out faster when cutting harder alloys but IBC averages three to four blade sharpenings per week.
“We don’t have a problem with tolerances and it’s fairly easy to change blades,” Horner says, adding blade changes usually take about 15 minutes. “If we’re running really hard material, naturally we may have to change the blade more than four times a week and we also have different diameter blades being used depending on the different thicknesses being cut—so even if a blade isn’t dull, we might have to put a different blade on our Oliver plate saw or SMID plate saw to adjust for the thickness of the plate.”
IBC relies on a number of features offered on Phillips’ saw blades. The spindle speed of the plate saws IBC uses determined the need to use carbide-tipped saw blades. “Tungsten carbide can handle the heat generated by the sawing of the material, as well as the abrasive qualities of the copper being cut,” says Jeff Chynoweth, president of Phillips.
Ferrous cutting cold saw blades are manufactured from M2 and M35 high speed steel. “This type of saw blade is a very specific tool used in slow rotating spindles, ranging from 15 rpm though 100 rpm,” says Chynoweth. “The teeth of a cold saw are ground into the plate.”
In the case of IBC, carbide-tipped saw blades are preferable, because of the way the blades wear down compared to standard cold saw blades. Chynoweth says one servicing difference between standard cold saw blades and carbide-tipped blades is that after carbide teeth have been sharpened many times, they become small and ineffective. At that point the carbide tooth typically can be replaced. However, a standard cold saw blade loses valuable side clearance after many sharpenings, rendering the saw blade ineffective.
There are many grades of carbide used in saw blades, ranging from very brittle to very soft. Choosing which grade to use depends on the material being cut. The hardest grade of carbide does not necessarily produce the best cutting results. “Even the silver solder used to braze the carbide teeth to the saw plate differs from one application to another,” Chynoweth says. The biggest differences: The blade’s rotational speed, feed rate, number of teeth on the saw blade, number of teeth in the cut and clearance angles on the carbide teeth.
Adjustments
For cold saw users cutting thin-walled profiles and tubes, Phillips has developed a variable pitch tooth pattern named Phillips Grind. “This particular grind applies industry-exclusive geometries with a variable pitch tooth pattern, similar to the technology found in band saw blades,” Chynoweth says. The Phillips Grind has a staggered tooth pitch and improves surface finish while reducing harmonics and vibration in thin-walled extrusions.
Through the years, IBC has determined which angles work best for cutting different copper alloys with varying thicknesses. “Phillips keeps track of what they need to supply us,” Horner says. “If we’re having trouble with the blade run and can’t figure out what it is, they send someone to evaluate our problem and offer solutions.”
When it comes to sawing, Chynoweth says, “The customer cannot be the only expert on their specific material. Our carbide and cold saw departments must be educated on various properties of the material our customer is sawing.”
The company’s latest grinding center is a Vollmer CHD270. The fully automated center has five CNC-controlled axes that move within 0.001 mm, which Chynoweth says is assisting Phillips as it advances grinding techniques.
“While manufacturing or updating the carbide teeth, we grind the tangential, radial, back and face angles to the correct specifications, depending on the application,” Chynoweth says. “Phillips develops numerous geometries for the saw tooth to ensure the blade meets the customer’s cutting needs.” (See “Anatomy of a carbide tooth.”)
“Our goal is to have customers concentrate on their own manufactured products,” Chynoweth says. “We will concentrate on their saw blades or other cutting tools.” Such astute attention helps minimize downtime since building a custom saw blade is not a one-size-fits-all option. “We have 24-hour emergency turnaround service available to our customers. The last thing we want is our customers shutting down their saws,” he says.
“Our main business is machining and forging copper and copper alloys,” Horner says. “We competitively sell all over the world so it’s important we provide our customers with length and width that is free of defects and in good finished condition. To compete successfully, it is always important to have vendors who are there to support you as Phillips helps us.”
Competitive pricing and the company’s responsive customer service have drawn IBC to Phillips and sustained their relationship. “If we have an issue or problem, they come down right away and try to help us solve it,” Horner says. “Phillips has excellent customer service. We’ve been using their blades for a really long time and we’ve changed up configurations here and there to figure out the best combinations. They make deliveries to us once a week and we can depend on them at any time to help us out.” FFJ
ANATOMY OF A CARBIDE TOOTH
Tungsten carbide is brazed into a seat pocket on a steel saw plate, referred to as the saw tooth. The side clearances of the tooth are ground first. A CNC machine grinds the tangential and radial clearance angles at the same time. The saw blade then goes to a
topper/facer, a CNC machine where the top clearance angle and hook angles are completed in two separate operations.
The carbide teeth on a saw blade become dull from two major factors: Heat generated by the sawing action and the rubbing action of the teeth sawing the material. The most vulnerable parts of the carbide teeth are the sides, which form the kerf, and the top. This is the widest point of the saw blade and where the saw blade does the cutting. Teeth become dull in two areas: Down the long face (hook) and on the top. When sharpening the saw blade, it must be faced to grind the hook angle again, as well as for grinding the clearance angle.
During normal wear, a carbide saw should last from eight to 12 sharpenings before it is no longer useable. When the carbide teeth become small and lose their clearance, the blade needs to be re-tipped with new teeth or thrown away. Source: Phillips Saw & Tool Inc.
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