Hartman Enterprises Inc. is a business built on multi-tasking machine tool technology. And from the moment the Oneida, N.Y., shop powered up its first multi-tasking machine in the early 1990s, and even to this day, it has one primary production objective for that type of equipment. That objective is to eliminate secondary operations involving multiple machines for as many different workpieces as possible.
Up until about 2000, Hartman successfully achieved this objective for a lot of its parts. However, there were a myriad of others that the shop believed could also be processed complete in single setups with multi-tasking technology. Unfortunately, these parts were a bit more high precision and complex, and the shop’s existing multi-tasking machines lacked the necessary accuracy and rigidity to process them.
Hartman decided it was time to update its multi-tasking capability and added seven new high-production multi-tasking machines featuring twin spindle/twin turret configurations for DONE IN ONE machining capability. These new generation machines provide the increased rigidity and accuracy the shop needs to tackle more complex parts as well as those larger in size that are too big for the shop’s Swiss-style turning machines. But most importantly, these new machines significantly expand the range of production parts Hartman can process in single setups on one machine and do so with shorter cycle times and in lights-out operations if so desired.
The shop’s new multi-tasking machines include three MULTIPLEX 6200-II MY Multi-Tasking machines and four HYPER QUADREX Multi-Tasking machines (one 150 MSY and three 200 MSY models), all from Mazak Corporation. The MULTIPLEX machines enhance Hartman’s single-setup, mid-size lot production and continuous operations through the incorporation of dual spindles, dual turrets with milling tools and Y-axis capability.
The MULTIPLEX 6200-II Ys allow Hartman to now handle bar work diameters up to 2”, shaft work lengths to 21” and chucked workpiece lengths to 7”. They provide a standard machining diameter of 10.24” and a maximum swing of 12.6” in diameter.
Also with twin-spindles and twin-turrets, Hartman’s HYPER QUADREX Multi-Tasking machines increase part-processing opportunities for the shop, including enhanced DONE IN ONE capabilities where it can completely machine parts from slug or bar fed material in single machine setups. Additionally, the balance cutting of the machines’ upper and lower turrets boosts the shop’s part throughput for a wider range of workpieces. Two of Hartman’s HYPER QUADREX machines have 8” chucks in their main spindles and collet chucks in their second spindles, while the other two use 10” chucks in their main spindles and collet chucks in their second spindles. For automated continuous production, the shop outfitted all the machines with 6-ft bar feeders.
Thanks to advanced multi-tasking technology from Mazak, the list of major industries Hartman serves is now very diverse. The shop produces components for everything from industrial pumping systems used in chemical plants and the paper industry, to explosion-proof electrical fittings and fixtures, to freight train braking systems, construction equipment, as well as steam engine turbine blades for the power generation industry.
On average, the 60-person shop puts out 60 jobs per month with lot sizes ranging from one to 2,000 pieces. Plus, it has several blanket orders that will involve even higher volumes. At any given time, there can be as many as 380 active jobs circulating around the shop floor at Hartman, requiring such operations as turning, milling, forming and welding.
With so many jobs running through the shop, Hartman’s process engineer Charles Mancuse will generate a traveler that indicates the ideal machine on which a job should run. The process starts with Mancuse’s experience and knowledge of the shop’s machining capabilities. If for some reason the ideal machine is already booked, he’ll assign the job to a second machine choice. He looks very closely at a part’s level of complexity when determining the primary machine on which it should run, which is typically one of the Mazak Multi-Tasking machines.
Because of the increased rigidity and accuracy of the Mazaks, Hartman processes a lot more components from challenging materials such as stainless steel, Inconel and Nickel 200 with required tolerances from +/- 0.010” to +/- 0.0005”. And most are produced from either round, hex or square-shaped bar stock between 1” and 2.5” in diameter. Bar stock is closer to finished part shapes, reduces the amount of material needing to be machined and helps save on raw material costs.
According to Russell Harrington, shop manager at Hartman Enterprises, the parts done on the Mazaks are tight toleranced ones the shop used to struggle with or those with specific surface finish requirements. For instance, a brass component for a train braking system done on the shop’s MULTIPLEX 6200-II MY requires holding an I.D groove to within +/- 0.001” and an I.D. bore diameter to +/- 0.0002”.
The identical twin spindles and identical twin turrets with Y-axis travel of the MULTIPLEX machines allow for highly efficient, accurate and flexible machining of such parts as the train braking system component as well as other unique parts. Long shaft parts, for instance, can be held using both spindles and machined with synchronized spindle rotation. Or, as is often the case with Hartman, the first operations of parts can be done with the No. 1 spindle/turret, and then parts automatically transfer to the No. 2 spindle/turret for completing remaining operations.
Or the shop has the option of completing two parts simultaneously and independently at both spindles/ turrets. The twin spindles on the MULTIPLEX machines each offer a bore size of 2.4” in diameter, and each delivers 30 hp and maximum speeds of 5,000 rpm. Since both spindles offer identical performance, part-processing flexibility is greatly increased.
The machines’ twin VDI-type turrets hold 12 tools each, and rotary tools can be mounted in any position. Machine Y-axis travels measure +/- 2” and live tooling capabilities of the turrets further increase productivity for Hartman.
The twin opposing turning spindles on the HYPER QUADREX machines operate together or separately. They allow a single part to be machined on all surfaces through a coordinated “hand-off” between spindles. Or Hartman has the option to machine two different parts simultaneously on the machines. Both spindles have full C-axis CNC control for part positioning and contouring with indexing increments of 0.0001 degrees.
Like the turning spindles, the twin turrets of the HYPER QUADREX machines can also operate independently or together. This capability means that Hartman has the versatility to either simultaneously machine two different features on a workpiece or follow a balanced machining strategy where two tools work together on the same workpiece feature.
Harrington illustrated this capability by describing the processing of a highly proprietary part that is simple in appearance, but very complex, done on one of the HYPER QUADREX machines. One end of the part is turned and a bell shape machined on it while chucked in the machine’s main spindle. At this point, the part is no longer completely round and transfers to the machine’s second spindle equipped with a two-jaw chuck because of that reason. Then in the second spindle, the part is bored through, reamed and threaded. Even with having to transfer the part from the main spindle to a two-jaw chuck in the second spindle, he said that the HYPER QUADREX easily holds all the part features concentric with one another to within 0.002”. Plus, it consistently generates surface finishes with zero imperfections as is required for the part.
Also with one of its HYPER QUADREX machines, Hartman was able to more than double its production of particular shaft sleeves for pumps. Again, a part that is simple in appearance but very complex. Made from stainless steel, Nickel 200, C276 and other exotic materials, the sleeves require a 16 Ra surface finish on all their surfaces. Their O.D.s must be held to +/-0.0005” and bores to +/- 0.0007”. Within the bore is a critical undercut that must be held to size within +/- 0.001”, and all the part features have to be concentric with one another within 0.0001”.
The HYPER QUADREX generates the required surface finishes, consistently maintains all the part tolerances and machines the sleeves as fast as possible. In fact, it increased production from 32 to 70 complete sleeves per day. Also because of the machine’s rigidity, Hartman has been able to reduce the number of rough milling passes and the tools needed for them. This, in turn, further shortens part cycle times and increases machine throughput – in some cases, doubling it.
“We can take less rough cuts and deeper finish passes while still maintaining surface finish requirements. For instance, on a stainless steel part, we are roughing at 800 sfm and feeding 0.015” with a side depth of cut of 0.100” and finishing at 1,000 sfm taking 0.010” per side and 0.006” feed. And generating a surface finish of Ra 32,” said Harrington. “So as opposed to doing maybe two rough passes and two finish passes, we’ll do one rough and one finish. Or, we will rough and finish with the same form mill tool – as opposed to a cutter for roughing and separate one for finishing – so less tooling is required, which helps lower cost per part.”
In addition to improving roughing operations at Hartman, the rigidity and accuracy of the Mazak machines has helped the shop further shorten part cycle times by optimizing drilling processes. Harrington pointed out that on the Mazaks, the shop not only runs drills that would cause some of its other machines to stall out but also runs them at higher speeds than they ever have in the past.
“We used to get a lot of chatter in our drilling operations, so we would first drill a pilot hole then open it up with the finish size drill. Now, we drill right to size,” said Harrington. “And since we opted for the tool monitor feature on our Mazaks, we can use it to determine drill life and can change out worn drilling tool inserts before they break.”
Both left and right spindles on the MULTIPLEX machines, for instance, are equipped with Mazak’s Tool Eye tool monitoring unit, which is standard on the Mazaks. When tool tips are brought into contact with these units, the Tool Eye data management system automatically registers the tool position information to the machine’s CNC. The system can also be used for tool measurement and tool breakage inspection.
Possibly the longest part cycle time at Hartman is 10 minutes. But within that time, there could be several different milling operations as well as those for turning. In fact, the shop often processes jobs that require as many as 10 milling tools, which equates to 10 live tool positions in the 12-position twin turrets of the Mazak machines. Additionally, Harrington said that extremely fast tool turret indexing times and not having to move the Mazak machines to their home positions for a turret index further contribute to reduced part cycle times.
“Multi-tasking is critical to our competitiveness,” commented Robert Sweet, president and owner of Hartman Enterprises. “In addition to performing multiple part processes in single setups, we often have one machinist running two or even three of the Mazak Multi-Tasking machines simultaneously. So essentially in these instances, we are putting out the work of four or more conventional machines and doing so with only one person. On top of this, we confidently run the Mazaks unattended over night.”
For lights-out part processing, the shop targets long-running jobs, such as those for blanket orders. The Mazaks are equipped with the best possible tooling, their counters and tool monitors are set and the machines run. The shop initially sets the machine tool life monitors during the first couple hours a job runs – steadily advancing cutter speeds and feeds until performance is optimized, then noting the exact life span of the tool. This process is carried out during the day shifts, and once exact tool life is determined, the job will then run lights out over night. And Sweet pointed out that these are jobs requiring that some very tight tolerances be held.
Quite often, Harrington will work up two programs for the same part. One that’s a bit more aggressive and will run during the day when there is someone to check on the machines, then a second more conservative program for overnight. This second program may involve a longer cycle time, but the machine is running unattended with no labor involved.
“Processing parts exclusively with conventional 2- or 3-axis lathes would make it impossible for us to compete,” said Sweet. “Our part volumes require multi-tasking and lights-out production. And basically, lights-out production is just a matter of having good tooling and machines you can depend on to hold tolerance. For us, the consistent and reliable Mazak MULTIPLEX and HYPER QUADREX Multi-Tasking machines make that happen. The machines are just so stable with no fluctuations and excellent repeatability. Plus, their chip evacuation is highly effective, which is also critical to unattended operations. We don’t experience any bird nests or chips in chucks with the Mazaks.”
Sweet said that the shop plans to further increase its part-processing capabilities, taking on more jobs involving larger sized multi-tasking work. And the Mazak machines will continue to play a key role in setting the shop apart from the competition in terms of versatility and speed and maintaining a “no secondary operations” part production objective.