Jake Grainger says he always had a mechanical bent, and 38 years ago when he first walked into a screw machine shop, he was hooked. Then, in 1973 he and his brother Gary borrowed some money, started their own shop, and essentially worked for no pay for 5 years to finance the company. They started Alpha Grainger in a tin garage in Natick, MA, with two Brown & Sharpe screw machines, moving over the years to its current location in Franklin, MA.
Since then, he has not looked back and has built a strong business, producing and delivering precision parts to automotive, mechanical, electronic and other customers. “We think of ourselves as part of our customers’ manufacturing process, even if some of them do not.”
He is a very hands-on shop owner.
“I have run every machine we have here. I like the process. I like bringing in new stuff. And making sure my people are able to use a new piece of machinery to its maximum capability”, he said. “I still love what I’m doing, working with great people”.
Jake knows speed and capability is essential in his machines, many of which he and his staff designed and built, nearly all of which he created the controls for, even to the extent of replacing or modifying factory controls and software.
“I have always seen that my machines could do things better or faster, but the manufacturers never permitted the capability to make improvements, so we started building our own controls,” Jake said.
“The machine builders are not the end users. Some have a fair idea what we do and most have no idea what we do. We bought a machine that was intended for parts up to 40 mm but it had terrible software bugs, and the builder refused to do anything about it.
“The machine would always hang on the last line of the program (M30) for a few seconds and then sometimes hang on that line of code for many minutes. We put up with this for over a year with many software glitches unaddressed. The machines still have issues, such as large dimensional changes due to temperature variations over the course of a day. But because there was nothing like them, we were making money with them. We could handle the complex work that was left after the simpler parts went offshore. Up until then it was high-volume multiple spindle screw machine work.”
Then Jake saw the INDEX C100 advertised in the trades.
“The INDEX machine I looked at, the 14-axis C100 production turning machine for complex parts, I first noticed in an ad. At the time, it was the better part of $250000 more than a similar Japanese machine. But when I learned about the INDEX bar loader, I realized we would be able to run our hex jobs at full speed continuously.
“The nice thing about being the decision maker and the guy that has the money is I don’t have to ask anyone what to do or if they think some idea is OK. I don’t need to figure out ROI. If I want to act on instinct I can do that. So I bought the INDEX. And I was right.”
The INDEX C100 Jake ordered has three 10-position tool turrets with two Y axes and identical motorized, liquid-cooled main and counter spindles. The machine is designed for fast, cost-competitive production of medium complexity parts turned from bar stock to 42 mm diameter. The C100 also comes as a 30mm machine with three 14-position turrets. Ideal for small to medium lot sizes, the machines deliver high performance within a small floor space, and are targeted to handle fixed headstock work often run on Swiss-type machines.
According to INDEX, 80% of the so-called Swiss machines working today are actually making fixed headstock-type parts in the 1-1/4 in. range. Although the Swiss-style machines are built to handle this bar size range, it is a misapplication of the Swiss-style sliding headstock technology, so INDEX developed the C100 which offers greater tooling variety, high precision, more power, and faster processing speed, plus greater flexibility.
The C100 with 42-mm bar capacity is available with 7000-RPM spindles. Both versions can run parts to 200 mm in length. The C100 drives are powerful: 25/29 kW (100% / 40%) for the 42 mm version.
The machining flexibility of the C100 is a keynote of INDEX technology. Up to three tools can be at work simultaneously with both Y axes and back working at the same time. And the counterspindle with linear-motor driven Z-axis can be synchronized with the travel of turret 3. Counterspindle pick-up from the spindle is accomplished in just 1.5 seconds.
That’s a lot of capability, but Jake really likes the INDEX bar feeder.
“In our view, one of the most important feature of the INDEX C machine is the bar feeder. Other bar feeders do not address the issue of high-speed spindle capability and bar rattle. We even build our own for some of our other machines because other bar loaders are not capable of running the stock at the speeds the tooling is capable of. The machine has to slow down to accept the new bar.”
In the INDEX bar feeder, the bar is supported by a series of ball bearings 8-10-in. apart which effectively prevents stock whipping or rattling in the feeder. The pusher is slightly smaller than the bar diameter in order to push the remnants through the spindle.
In most feeders, the pusher collet is larger than the diameter of the bars. That leaves room inside the feeder for bars to whip and rattle, especially during high-speed operation. Even hydrostatic bearings are not totally effective. Jake has found that throwing oil in the bar channel sounds like a great theory, but it doesn’t work--especially with hex stock because the hex corners wipe away the oil.
“The INDEX feeder allows us to continuously run the parts to the top speed of the spindle, 7000 rpm, without slowing the spindle for the bar loader, even with hex and square stock,” Jake said.
Smaller, but more rigid
Reducing the size of the machine put turrets and parts closer together, so traverse distances are shorter and the bulkiness a larger machine would require in order to provide rigidity is not necessary. “It is actually more rigid than the larger machine and we can do tough parts on the INDEX we could not dream of doing on the other machines.
“Try to put a form tool in anyone else’s turret, and it will chatter like crazy,” Jake said. “INDEX turrets are way more rigid, which is good for us as we use form tools on some parts.”
Physically the C100 is smaller, but it uses an unusual method of generating X and Z moves
The turret slides move in the X- and Z- directions on innovative single-plane guide ways. This permits rapids up to 2400 IPM and accelerations up to 1 g with maximum rigidity. The plate-type guide way of the turret slides also means turrets glide directly on the machine bed, assuring high stiffness and dampening, resulting in longer tool life and better surface finish.
Simultaneous machining with two Y axes at the main spindle or a Y axis at the main spindle and also one at the counterspindle—each with 70mm travel—gives users the option to divide machining operations for optimum machining efficiency and flexibility This freedom also is a key to reduced cycle times. For example, users can machine simultaneously with up to three driven tools for complete machining in a single set-up, including heavy milling, and backworking.
INDEX machines typically use Siemens controls. Being a controls expert himself, Jake likes the Siemens 840D.
Other machines often are equipped with Fanuc--the Prius of CNC, according to Jake. “Model shops like Fanuc because they don’t care how long it takes to complete a part. But we are totally cycle-time driven. I earn a living by renting machines to my customers. The faster I can make a part, the less time in it, the more likely I can underbid my competitors. Cycle times are critical,” Jake pointed out.
The Siemens CNC is easy to work with; plain text is used in display and operation and the screen shows all spindles and axes at one view. Superior programming with more than 70 user routines offers practical support down to the finest detail. Absolute measuring systems know axis and tool positions in every situation.
“The Siemens control captures all the job data and settings and stores it for the next time the part is to be run. The Fanuc doesn’t capture any of that,” said machine operator Eric Green. “I can get all my tooling ready off-machine--preset the tools and put their dimensional information into the program--so tools are ready to work the instant I lock them into the turret without having to touch them off.”
Each position on each 14-station turret is equipped for preset driven tools. Large tooling capacity means short setup times and very fast cycle times even for small batches. Tools are more easily accessible than on a Swiss machine and can be changed quickly. They lock with only one screw, and because of the INDEX-designed tool holder mating surface, the tool location is extremely repeatable and rigid.
“Some may feel they don’t want to learn a new control,” Jake said, “but with a positive attitude they will have no trouble learning the Siemens. They will end up loving the Siemens control and may even wish their Fanuc controls were more like the Siemens.”
The Siemens control is way faster and capable of running the machine much faster than the Fanuc can, according to Jake. (The Fanuc processor in Jake’s view dramatically impairs the control’s ability to position axes quickly--a major deficiency in a machine tool that is designed mechanically for high speeds.)
“If you took a program off the Fanuc and put it in the Siemens control, idle time would be reduced up to 50%’” Jake said.
Programs are written by hand at Grainger. Lathe programs are never very long, so they feel it is faster to write them manually. “Maybe 5-10 lines of code per tool and you’re done,” Jake said. “We do lathe programs in the text editor off-line. We’ve found that keying a lathe program into a CAM system actually takes longer than keying it into a text editor and downloading it into the Siemens control,” Jake claims.
One reason the INDEX is faster.
“One of the Japanese multi-task machines we have has a top spindle speed of 6000 rpm and the machine takes 4 seconds to reach that speed, and another 4 seconds to go back to 0. The INDEX C100 takes less than 1 second. Most spindle speed changes occur due to tool changes. The INDEX spindle can be at the new speed faster than the tool can be there so there is never any waiting for the spindle to reach speed. That’s because it has an integrated spindle drive which eliminated the inertia of pulleys and belts.
The C100 is configured to complete a wide range of parts from simple to complex, small to large batch sizes, so users can expect extremely high machine utilization rates, which allow the C100 to be very cost-effective. The part transfer robot quickly unloads parts from the main or counterspindle.
Eric says, “When we turn on the INDEX in the morning, there is no spindle warm-up period, and we are making good parts right away all day. On our other machines, thermal compensation was a big issue. INDEX addressed this concern by chilling the drive and castings, and uses glass scales. On a recent run, the machine was producing 2 brass parts per minute, 1000 a day with no trouble at all and no thermal variation.
Jake now has such confidence in the performance and value of the INDEX C100, that he decided to unload his three Japanese brand multi-task turning machines—all less than 4 years old—and replace them with two more INDEX C100’s and a C200 production turning machine, which has main spindle and counter spindle with 65 or 90 mm bar capacity.
Justifying the purchase
How does Jake justify the cost of an INDEX? “On one of our parts we were getting paid for a 52-second cycle time on the other machines. With the INDEX, we can drop the part complete in 29 seconds. We don’t have to slow down the machine on hex jobs, thanks to a great bar loader.
“The cost of the machine tool divided by the number of years you have it reduces the cost of the machine to very little. Running over two shifts, the cost basically goes away. The more important cost is paying the guy that runs the machine. Having a highly productive machine that runs all day solves that problem.
“It’s hard to predict ROI before you get the machine” Jake continued, “but if you come at the machine, say machine ‘X’ is $400000 and this machine is $600000, and you divide that over the years you have it, that’s only about $2000 a month for a much better, much faster machine. Then the question becomes, can this generate more than $2000 new revenue a month and the answer is resoundingly, ‘Yes!’. So it is not that hard a decision to make if you come at it from that point of view.”
With the dollar recently able to buy more in Europe, European machine tools have become much more price competitive than they were even a year ago.
Much of what Jake has learned over the years still serves him well. And he learned everything: from controls, to programming to machine operation to purchasing. It has given his shop an edge in creating the processes they use to profitably produce precision parts. The latest edge is the C100 from INDEX.