Mazatrol Fusion 640 is the name for a new machine control recently introduced by Mazak Corp. (Florence, Kentucky). The control is available on the company’s full line of machine tools, including horizontal and vertical machining centers, turning TNGG Insertcenters and multi-tasking machines.
According to the company, this is not a PC-based CNC, although it utilizes PC technology. Rather than simply mounting a PC front-end to a CNC, Mazak has fused the two (hence the name). This fusion allows bi-directional communication between the two computers.
The CNC side of this dual-processor design uses a 64-bit central processing unit (CPU) to execute programmed functions for metal cutting operations. In addition, it is designed to extract information from the machine tool, such as servo-motor loads, and to use that data to suggest improved machining parameters. These suggestions are accessible to the operator using the 32-bit PC CPU.
With this two-way information flow, the control automatically optimizes the process. Instead of making trial cuts to tweak a program, a shop can get the information necessary to maximize cutting speeds and feeds before the first chip is cut.
A control feature called Navigator segments the cutting cycle into time periods. Starting with the longest time period, the operator or off-line programmer can "ask"tungsten carbide inserts the CNC for suggestions on how to reduce that part of the cycle. Drawing from its database, the control makes a recommendation. What-if scenarios can be carried on for every other segment in the program to find the best approach. The CNC looks at programmed feeds and speeds and determines what percentage of the machine tool’s maximum capacity, then calculates how much capacity is left and makes its recommendation based on that difference.
The control will be offered in three distinct versions, one each for the company’s turning centers, machining centers and multi-tasking machines.
One of the first clues that Precision Plus is different from other machine shops was a gentle clicking noise. The sound emanates from more than a dozen mechanically driven Swiss-type lathes at the center of the shop floor. Lined up in neat rows and serviced by obviously newer barfeeders, these machines cut uncovered, without the noise-damping enclosures that characterize the shop’s CNC machines. A closer look reveals a half-dozen or so tools simultaneously plunging in and out of the workpiece as the cams rotate.
Some of these machines had already been producing parts for years by the time the company moved to its current location in Elkhorn, Wisconsin in 2000. Under the leadership of company president Mike J. Reader, the company has since added various newer CNC equipment, including Miyano ABX and BNX two-spindle lathes as well as multiple Star and Tsugami Swiss-type CNC lathes. And yet, Precision Plus still relies heavily on equipment that operates in much the same way as it did when Reader’s father, Phil, first purchased the company in 1988 – that is, by using physical cams rather than CNCs to space out the timing and depth of cuts. Why?
This was my first question to Michael P. Reader, VP of Engineering (and Mike Reader’s son). His answer was simple: “The cam-driven machines, when they can be used, are cheaper to operate,” he says.
“For small cylindrical parts with higher annual volumes, the Swiss cam machines are very economical,” says Reader. The fleet of mechanically driven Swiss-type lathes from Tornos have lower electrical costs, and crucially can often cut parts significantly faster.
That last factor might be surprising to some, as a computer-operated machine tool seems like it should have no problem competing with a machine that has absolutely no computing power whatsoever. However, the cam-driven machines can utilize multiple cutting tools at once, with very little travel. “All the tools are at rest less than two inches from the part,” Reader says, gesturing to a semicircle of cutting tools frantically cutting a firing pin out of a thin bar. “This makes it much faster than a CNC.”
How much faster could it be? “We have one part that would take eight seconds per piece on a Swiss CNC,” Reader says. “On the cam machine, it takes three seconds.” More than doubling production speed is a major difference, especially when dealing with high volumes. “If we had to use a CNC on that part,” he says, “we wouldn’t even break even.”
But when are the CNC machines preferable?
“It really depends on the needs of the part,” Reader says. “Some parts need increased precision, which a Swiss CNC provides.” Take the example of a dental component the facility produces. At one end, the diameter is only 0.01 inches thick, and its length-to-diameter ratio is quite high, so it requires additional support to eliminate chatter and prevent breaking the component off in the machine. These features of the part make the CNC necessary, as it is capable of higher precision and greater rigidity. Additionally, surface roughness must be nearly flawless, as a slight imperfection can be catastrophic. “We need to make sure we hit the tolerance exactly,” Reader says. “If this dental component had any surface imperfections, it could lead to crack propagation and failure during use.”
I think anyone who has sat in a dentist’s chair is grateful for the increased precision of the CNC machine.
Factors other than tolerance can play into the choice to use the CNC machines. For starters, they can handle larger parts – 12, 20 or 32 millimeters, depending on the machine. Additionally, parts like the dental component require high-pressure coolant, which is not possible in the cam-driven Swiss lathes. Coolant can also be a major factor for materials that generate stringy or sticky chips, as well as valve components with O-ring’s grooves that require high pressure to remove chips.
Finally, the headstock lathes find work with larger and more complex parts up to 2.5 inches in diameter. “Generally, when we have lots of material removal or a higher degree of complexity, we’re going to utilize our Miyano platform,” Reader says. The Miyano ABX is used for aggressive and precise machining – in part due to the hydraulically operated chucks and the robust machine design the platform offers. One part used in semiconductor production involves a great deal of ID material removal, off-center drilling, threading and OD turning on high-tensile, high-yield stainless steel. On a two-spindle lathe with three turrets, the component can be machined complete in one operation at a highly competitive rate.
The other lathe – the Miyano BNX – is primarily there for its efficiency. “The BNX offers faster production rates surface milling cutters than the ABX while also allowing for fifth-decimal offsets,” Reader says. Precision Plus machines components plus-or-minus 1 ten-thousandth of an inch on OD turning, and a total of 3 ten-thousandths on ID bores. When it does not need to be quite so precise, it is capable of machining simultaneously on the main and sub spindle with the single turret, which increases throughput on many parts. Both platforms are equipped with quick-change chucking systems from Hainbuch to improve setup time and part concentricity from spindle to spindle.
As with many things in machining, it really comes down to the part. “In general, the larger and more complex the part, the more likely it is to go on the fixed headstock lathes,” Reader says. “Smaller cylindrical parts with extremely tight tolerances or that need tube process inserts high-pressure coolant go on the Swiss CNC machines. But if we can make it on the Swiss CAM machines, it will likely be faster, and just as precise, to be produced there.”
Mapal’s HighTorque Chuck (HTC) with narrow contour combines the benefits of hydraulic expansion with 3-degree back taper. This fast feed milling inserts feature is accomplished via additive manufacturing, which enables the clamping range to be positioned very close to the chuck tip for an optimum radial runout of less than 3 microns at the location bore and less than 5 microns at 2.5×D as well as high shape accuracy and good vibration damping. The damping in the system reduces microstructure cracking at the cutting edge, which in turn ensures longer tool life and less strain on the machine spindle. Furthermore, Mapal explains, the additive process eliminates the need for the soldered joint that has been a limiting factor until now. This chuck shares the benefits of the standard HTC, including thermal stability. Operating temperature ranges to 338°F (170°C), promoting additional process reliability.
With benefits for moldmaking as well as automotive and aerospace applications, rod peeling inserts this chuck is designed for all machining operations in contour-critical areas.
The chuck is available in clamping diameters of 6, 8, 10 and 12 mm for HSK-A63 and SK-40 interfaces. Intermediate sleeves enable additional diameter ranges to be covered. In addition, the chuck is optionally available with a dynamically-balanced HSK connection.
Tungaloy has expanded its TungForce-Rec series of indexable square shoulder milling cutter. The series’ high insert density now includes 6 mm (.236″) diameter cutter bodies, which is said to be the smallest indexable shoulder mill available in the market, as well as size-04 inserts that are designed for axial cutting depths of up to 4 mm (.157″).
Featuring the V-bottom design of TungForce-Rec inserts in a compact form, the new size-04 inserts enable the cutter body to have a large core diameter and ample insert support, providing high tool rigidity and stability contrary to the small diameter.
The small size-04 inserts also enable TungForce-Rec04 to have a higher teeth density than conventional shoulder cutters of the same size, boasting two BTA deep hole drilling inserts teeth for an 8 mm diameter cutter and three for a 10 mm. This reportedly enables TungForce-Rec04 to run higher feed speed than competitors when being fed at the same rate per tooth, enabling increased productivity.
The insert design provides the flank face with an obtuse clearance angle for enhanced cutting edge strength and sharpness. Two insert grades are available: AH3225 is the first choice for steel and AH120 is suited for cast iron. According to Tungaloy, both provide high reliability and long tool life for extremely high shoulder milling productivity. rod peeling inserts 16 new inserts and cutter bodies are introduced in this expansion.
Turning center cutting tools vary from one type to another. When the turret rotates a cutting tool into position, the cutting edge of a turning tool will be in a different position than the cutting edge of a boring bar, a drill or a back-turning tool. Even with similar cutting tools—possibly even qualified tools such as turning tools—the cutting will not be in precisely the same position for each tool. Differences in tool shanks and inserts (and even the quality of placement in the turret) will result in a small deviation from tool to tool.
For this reason, turning centers require a separate program-zero assignment for each cutting tool. The accuracy of this program-zero assignment will directly affect how much trial machining will be needed when the first workpiece in a job is run.
I feel that the most accurate (and quickest) way of assigning program zero for turning centers is to use a tool touch-off probe. Although this device facilitates the task of program-zero assignment, many CNC turning centers don’t have a tool touch-off probe. If a center does have it, sometimes it is not used because people fail to see its benefit. This article assumes that you do not have or do not use a tool touch-off probe on your CNC turning centers.
Without a tool touch-off probe, the task of assigning program zero for cutting tools on turning centers is commonly referred to as “touching off” the tools.
I’m challenging you to a goal of completely eliminating tool touch offs for tools that remain in the turret from job to job. Many shops have accomplished this goal because it is achievable with most current models of turning centers. Eliminating touch off for these cutting tools should result in sizable savings.
Assuming that your programmer is using each coordinate in the program as the mean value of every tolerance band in every program, I contend that if a cutting tool is machining correctly in one job, it will continue to machine correctly in the next job. What could keep this from being true? Admittedly, if there is a dramatic difference in workpiece material from job to job (maybe from machining aluminum in one job to tool steel in the next), the tool pressure difference between materials will cause the need for sizing adjustments from job to job (not to mention the need for different insert grades).
Let me rephrase the question: What makes it necessary for your setup people to repeat the task of tool touch off for tools that remain in the turret from job to job?
For the X axis, the program-zero point is always the spindle center—the spindle center does not change rod peeling inserts from job to job. If a cutting tool is touched off correctly, and if the program zero assignment in the X axis is done correctly, diameters machined by the tool (even for the first workpiece) should be close to size. While tool wear will cause the need for sizing adjustments during the production run, when the production run is completed, and the tool is still machining properly to size, there will be no need to touch the tool off again for assigning program zero in the X axis for the next job. Even with a different workpiece configuration for the next job, the tool will continue machining to size (in diameter) when the next job is started.
Where is the program-zero point in the Z axis? Most programmers like to use the right end of the finished workpiece (the end opposite the chuck) as the Z axis program-zero point.
The bar peeling inserts trick is to find a more consistent Z-axis surface to use for Z-axis touch offs—a surface that doesn’t change from job to job. A good choice in many cases is the chuck face (we’re assuming the chuck isn’t replaced from job to job). Because the chuck face doesn’t change from job to job, there will be no need to repeat the task of Z-axis touch off for tools that remain in the turret from job to job.
What about the Z axis program-zero point? As stated, most programmers like to make the right end of the finished workpiece the Z axis program-zero point. If your setup people touch off the chuck face, does this mean all your programs must change?
Many current model CNC controls provide a way to shift the program-zero point, which means programs will not have to change. Programmers will determine the most logical program-zero point for developing programs, and setup people will be allowed to touch off a consistent surface.
For each job, the setup person will determine the distance from the chuck face to the Z axis program-zero point used by the programmer (right end of finished workpiece, for example). For the first operation of a workpiece, this isn’t overly critical. All that’s necessary is to ensure that material is left on the other end of the workpiece for the second operation. I’ve seen people measure this value with a dial caliper. For the second operation, this measurement is more critical. It controls the overall length of the workpiece.
Here is an example of how much this technique can save. Say there are five tools in your current job. The setup person touches them off and measures the work-shift value. The operator runs out the job. In the next setup, say the same five tools are used (no additional tools are required). In this case, only the work-shift value must be determined and entered.
