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Ten Cluster Tower Workholding System From
Kurt Utilizes Stepped Jaws Allowing
Machining On Three Sides Of Each Part -- -- Increases Output While Reducing
Setup Time
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Rick Vogel, manufacturing supervisor
for Parker Hydraulics, is shown holding a manifold block finish
machined in the company's Kurt CarvLock Cluster Tower System.
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Chanhassen, Minnesota: Parker Hannifin
Corporation (Integrated Hydraulics Division) is a world leader in the
manufacture of hydraulic cartridge products and integrated systems utilized
in fluid power applications. The hydraulic manifold blocks for these products
require precision machining which is done on a Mazak Palletech system
with two FH 4800 horizontal machining centers (HMC's) equipped with a
series of Kurt CarvLock Cluster Towers.
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| The Integrated Hydraulics Division of Parker Hydraulics
is a world leader in the manufacture of hydraulic cartridge products
and integrated systems. |
To maximize productivity for its diverse product mix, Parker Hydraulics
uses an extremely well-planned high density Kurt workholding system that
accommodates many different size manifold blocks in relatively small production
runs. Manufactured out of 11L17 and 12L14 steel, ductile iron and aluminum,
these manifold blocks are finished machined in several sizes with various
configurations of SAE ports, valve cavities, and threaded holes, most
with precision features. The manifold blocks range in size from 1 inch
to 15 inch widths and lot sizes average around 100.
"Our workholding setup allows us to maximize the output potential
of our Palletech system while it provides us with the flexibility needed
to handle the many different size manifold blocks for our product mix,"
reports Rick Vogel, manufacturing supervisor for Parker Hydraulics. "We
have 10 towers in the system with each tower holding 8 parts for machining.
There are two clamping stations per tower face, with each station equipped
with stepped clamping jaws. The center, stationary jaw is also stepped
to match up and provide the correct clamping dimensions for up to 15 different
size manifold blocks. By rotating the jaws in each station, we cover the
full range of needed sizes from smallest to largest without having to
change jaws."
The biggest advantage to the setup, according to Vogel, is that it allows
for maching on three sides of the part without having to unclamp, reposition
and reclamp the part. Steps on the two, non-clamping sides of the jaws
provide the needed clearance to do the required machining on three sides
of the part without having to change the jaws. The stepped jaw design
reduces spindle travel so that the system is in the cut all all times
delivering maximum productivity.
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| Stepped jaw design on the Kurt Cluster Tower handles
up to 15 different size parts simply by rotating the jaws. Quick change
feature allows repositioning a set of three jaws on one side of the
tower in less than a minute. |
Getting the most out of a system like this twin Mazak FH 4800 equipped
Palletech system is amazing to see in action. Parker Hydraulics uses both
to mill, drill, tap and bore. Both HMC's have a top speed of 12,000 rpm
with a chip-to-chip tool change time of just 3.0 seconds. They have a
rapid traverse rate to 1,968 ipm in all axes and automatic tool changer
which carries 120 tools. With X travel of 22", Y travel of 24",
and Z travel of 22", these machines are fast and can really take
advantage of the high density workholding setup by delivering maximum
productivity.
Clamping Rigidity Achieved With Kurt CarvLock
Cluster Tower's Ductile Iron Design
Parker Hydraulics requires close tolerances for its hydraulic
blocks which means the clamping system has to be extremely rigid. The
Kurt Cluster Towers are precision machined from 80,000 psi ductile iron
which gives the clamping modules the extra rigidity needed to achieve
workpiece immobility while dampening cutter induced vibration.
With four different jaw systems available for these Cluster Towers, Vogel
and his team opted for the machinable aluminum design for five of the
towers and machinable ductile iron for the second set of five towers.
This combination provides the best clamping force for different size manifold
blocks with the largest sizes held in ductile iron jaws and the smaller
ones held in aluminum jaws. By using Kurt's off-the-shelf jaws, Vogel
and his team saved time over designing their own, plus Kurt's quick-change
jaw feature is more efficient. Also, the quick-change feature allows removing
and repositioning a set of three jaws in about a minute which is done
while the towers are in the setup que. These movable and stationary jaws
repeat to .001 inch accuracy so there are no alignment problems when changing
the jaw setup. Another feature Vogel and his operators liked is the center
clamping area of the CarvLock towers are covered at all times so chips
and debris are kept out of the clamping mechanism.
12 Station Cluster Tower Setup Used For
Longer Steel and Iron Part Runs
Where lot size requirements for the manifold blocks exceed 200 and are
machined from 11L17 and 12L14 steel and ductile iron, Vogel and his team
use another high density Kurt Cluster Tower setup on a Mazak FH 588 HMC.
With 12 clamping stations (3 per side with potential for 4 on smaller
manifold blocks), this tower setup employs a new clamping module called
the WedgeLock. The WedgeLock has a serrated bottom which interlocks with
serrations on the tower surface.
The advantage of this design is that it is self-aligning so that setup
is faster with repeatable accuracy. The serrations on these mating surfaces
are precisely machined to provide .062 inch indexing between surfaces.
When these opposing serrations come together, they interlock forming a
rigid, level, and highly repeatable interface. Matching serrations automatically
aligns the surfaces, making subsequent reclampings highly repeatable.
Various size parts can be clamped quickly and accurately, similar to a
custom fixture, but with the versatility of a modular system. High density
is also the key in this workholding setup because three parts are clamped
closely together on each tower face, reducing spindle travel to a minimum.
Accuracy to ±.001 is held on these parts for milling, drilling
and tapping at speeds to 1700 rpm.
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| The Kurt Cluster Tower with WedgeLock
jaw has mating serrated surfaces which interlock for a rigid and highly
repeatable interface. This provides holding accuracy to ±.001
inch for Parker Hydraulics steel and ductile iron manifold blocks. |
"This workholding setup is a nice complement to the tower setup
on our Palletech system because it gives us versatility in machining various
size manifold blocks in hard materials and in larger quantities"
reports Vogel. "We also get the output we need in a single machining
center."
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