Previously manufactured on a horizontal machining center, these parts are now "Done-In-One" on the Mazak Integrex.

In December 2001, Bodine Electric (Chicago, IL) approached Machinery Systems to take a look at providing a better solution for the machining of their aluminum motor housings. Bodine was performing the required machining on three Horizontal machining centers, with an operator dedicated to each machine. The machining centers were approximately ten years old, and maintenance costs and downtime were steadily increasing. It was really hurting their delivery time, and obviously the cost of the parts were increasing. Another problem was that there was a lot of labor required to load and unload these parts. Bodine wanted labor content reduced.

We looked at this challenge and offered them with three options. The first option was the Machining Center option, specifically a two machine FH-4800 Palletech cell, incorporating 2 machining centers, and 12-pallets in the Palletech, with a unload/load station. Since reduction of labor was a critical, objective, we looked at utilizing a robot at the load/unload station.

The aquisition cost of this cell was going to be tremendous when we calculated all the fixture costs, which averaged about $40,000 per tombstone, with about a dozen castings to fixture on the tombstones. Additionally, the pick-and-place style robot on the load/unload station, would cost between $150,000 to $200,000.

The second option was a Mazak Variaxis 500 5-Axis machining center for machining the castings. While the Variaxis solution provided flexibility in attacking the machining challenges, it was ultimately discarded because all of the castings would require 2 chuckings, thus 2 machining operations in order to complete the required machining. While the 2 machining operations could have been accomplished with the aid of a robot, the combined fixturing and robot costs for the Variaxis cell were very high, similar to those of the machining center solution.

The third "outside the box" option was an Integrex 100SY with a gantry robot. With this solution, Bodine would be able to fixture or nest a minimum of 50 pieces per table, resulting in hours of unattended machining time. The flexibility of the Integrex, supplied with a sub-spindle, and B-axis would enable them to perform all required turning, boring, milling, and drilling, at whatever angle was needed. In the typical machining sequence, all features on the front end of the casting could be machined in the main spindle. The part would then be passed over to the sub-spindle, to perform all required machining on the back half of the casting, completing the part! Since tombstone fixtures would be replaced by chuck jaws in the Integrex system, the typical workholding cost would shrink from over $40,000 per casting to less than $5,000 (including the cost of Gantry templates and Gantry chuck jaws).

After looking at the alternatives presented, Bodine chose the Integrex solution for the following reasons:

1) The Integrex solution had the lowest overall acquisition cost, due to the drastic reduction in workholding tooling cost, and the lower cost of a Gantry robot vs. a stand-alone robot for loading & unload parts.

2) The operating costs were low. With the Gantry performing load\unload, the project could be implemented with a 2-machine cell, supported by only one operator, whose responsibilities are to fill the tables with castings, perform occasional part checks, and unload the finished parts from the tables.

3) With the ability of the operator to load up the Gantry tables with several hours of castings, the machines would be able to run unattended through break periods, lunches, and onto an unattended 3rd shift. With Bodine’s average machining cycle of 8 minutes, the fully loaded table would enable close to 8 hours of unattended machining time.

4) With Bodine’s average lot size between 100-200, quick changeover was an important consideration. The Integrex machines were fitted with quick change chucks on the main and sub-spindle. The chucks selected were a quick change SMW Autoblok, palletized type chuck for the main spindle, and a SMW Autoblok 3-jaw quick jaw quick change chuck for the subspindle. Utilizing these quick change chucking systems, both sets of jaws could be changed over in less than 5 minutes. The gantry table has templates already set up for each part number. They can change those over in 5 minutes. There’s a total change over time on this cell of under 10 minutes for each part.

In addition, the Integrex machines come standard with 40 tool magazines fitted, in this case, with Sandvik Capto quick change tooling. All the tooling is resident in each machine, so change over doesn’t require touching any tooling. All tooling stays in the magazine. The program is called up, including jaws on the main and sub-spindles are changed and the pallets on the gantry table are changed. On occasion, the gantry grippers are changed because of the way the stroke or diameters of the bores have to grab on to pick up these parts. This happens maybe one out of every four changeovers.

5) Compared with a machining center, the Integrex programs are much simpler and shorter. The inspection support is similarly reduced because Bodine no longer has to use their CMM to check the positional relationships for each of the 6 parts on a tombstone, instead they would only need to check 1 part.

After Bodine made the decision to order these machines, we shipped them to the Mazak technical center in Schaumburg, IL and started the part programming, and setting up the gantry and the machine with Bodine personnel. Our goal was to develop the Integrex cell to the point where we had production-ready processes developed for 2 castings on each machine. Following process development at the Mazak technical center, the machines were shipped to the customer’s facility.

Bodine is very pleased with the performance of the machines. One of their early concerns was tolerances, as some of their tolerances are very tight, .0003 to .0004 on the bearing bores. They were concerned with holding some of these sizes in an unattended environment, but to date they’re holding size on all these parts. The changeover time has been slashed compared to what it used to be on the horizontal machining centers, so Bodine is very happy.