Parts that took R.A. Miller Industries 25 minutes of machining with two lathe and three mill operations, now only took 6 minutes from bar stock to completion.
Five parts on this Hummer whip antenna, (two inside the base), are machined on an Okuma MacTurn 250 multi-axis, multi-task machine, with B-axis (tilting live tooling), and programmed with GibbsCAM 5-axis and MTM software.
R.A. Miller Industries (RAMI), of Grand Haven, Michigan, is a major antenna manufacturer housing 170 employees in over 100,000 square feet of office and production space. RAMI prides itself on building antennas "from the ground up," doing all the electrical and mechanical engineering, parts production, degreasing, plating, painting and assembly for their military, automotive (heavy truck), general aviation and marine antennas. For automotive antenna production, RAMI contracts for parts because the part volume requires 6-spindle and 8-spindle machines, for which RAMI lacks floor space.
In late 2009, RAMI was challenged because two key components of a military antenna required for the fulfillment of a long-term military contract of 3,000 units per month -- 6,000 to 10,000 parts a month -- were too complex for RAMI's machine tools, and too difficult for CNC programmers to program manually. The parts had to be contracted to a job shop. Soon, RAMI found that part deliveries were taking too long, that parts had become expensive, that its shop did not have full control of quality and delivery, and that deliveries were not synchronizing with assembly requirements.
The solution would be to acquire a new machine tool capable of multi-task and 5-axis machining, an MTM that combined milling and turning. Programming the machine tool would require a CAD system to develop accurate 3D part models, and CAM software capable of directly using the CAD models to quickly program complex parts for machining on the multi-axis MTM.
Image of Autodesk Inventor model of upper spring holder coming into GibbsCAM, showing the screen that allows users to select part model attributes, such as features and feature colors, to be imported and preserved for subsequent use with GibbsCAM automation functions.
In the late spring of 2010, the RAMI machine shop purchased an Okuma MacTurn 250, a multi-task turning center, and contacted their GibbsCAM reseller, who assured them that GibbsCAM could program parts for machining on any MTM or multi-axis milling or turning center, regardless of complexity, that it had a very short learning curve, and that its interface is very easy to understand and navigate for any machinist or CNC programmer.
For modeling machinable parts, Autodesk Inventor was recommended, because GibbsCAM's ACIS-SAT translator, assisted by Autodesk Inventor View, would read Autodesk Inventor files flawlessly. In addition the GibbsCAM Autodesk Inventor Add-in allows users to run GibbsCAM within Inventor, should an engineer or CNC programmer use both applications.
These are the various antenna parts manufactured on RAMI's Okuma MacTurn 250, purchased primarily to machine the ferrule, shown at center, in a continuous, untended part run from bar stock.
In June 2010, RAMI Engineering acquired Autodesk Inventor and, in August, after Engineering had become acquainted with Inventor, the RAMI machine shop acquired GibbsCAM. A RAMI engineer would produce part models for the shop when a prototype or release product was ready for machining. The CNC programmer-machinist would open the model in GibbsCAM to analyze the part, determine machining strategies, and generate and verify CNC programs to efficiently drive the machine tool. Rich Stenberg, the main MTM CNC programmer, found GibbsCAM easy to learn, easy to use and, in a short time, had the new machine tool producing the complex parts required to fulfill the military contract. He says, "I get all the parts for the MacTurn, and because of long part runs, I may go for months without using GibbsCAM. When I do, it just makes sense, and I jump right into it."
Within a month, the shop had the machine tool doing volume production of complex parts programmed with GibbsCAM from Inventor models.
The bar feeder, tool magazine and parts accumulator on the Okuma MacTurn enable RAMI to run parts untended for 10-12 hours.
The shop fulfilled the military contract on time, every month, and did so without the cost of outside machining services. RAMI's shop floor lead person states that the machine tool and software paid for themselves in under a year on that contract alone.
In its first year with GibbsCAM, the shop reprogrammed several parts for machining on the MacTurn, slashing production time. Parts that took 25 minutes of machining with two lathe and three mill operations, now take 6 minutes from bar stock to completion, and the MacTurn frequently runs untended for 10 to 12 hours for production runs. Moving to a single machine also reduced set-up and part handling, freeing 75% of the required labor to make more parts on other machines.
The business end of the 5-axis-simultaneous-capable Okuma MacTurn, machining an electronic antenna component on the main spindle. The MacTurn has a B-axis cutting head -- tilting live tooling that enables 5-axis machining with Y-axis offsets -- which uses a 44-tool magazine, while the lower turret has 12 tool stations.
Furthermore, the programmer-machinists now save hours of programming time because they use Inventor models as input to GibbsCAM. GibbsCAM allows users to take cross sections of the Inventor part models anywhere on the part, and to use them to program CNCs directly. Using Inventor models in GibbsCAM, the programmer-machinists now save programming time on both simple and complex parts for all their 15 CNCs. The software combination eliminates trigonometric calculations, eliminates trial and error, provides all the tools for programming and optimizing MTM machine tool use, and enables producing parts on demand, all at reduced costs in programming and machining time. With Autodesk Inventor and GibbsCAM, RAMI has eliminated all outside machining services for military and general aviation antenna production. Neither software, alone, could have met RAMI's requirement for CAD/CAM, but together they comprise a total solution for machining parts.
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