|A typical cell at Precision Aerospace includes different types of machines and both high-end and standard machine models. |
Precision Aerospace Corp. is on a vertical flight plan to success. Through vertical integration, the 100-percent aerospace and defense Tier Two shop continues to diversify and expand process capabilities to serve its customers better.
As a result of its vertical diversification, the shop’s capabilities run the full manufacturing gamut, offering everything from five-axis, EDM and Swiss style screw machining, to stamping, metal joining, assembly, testing, and kitting. And for many of these capabilities, the shop is accredited by the National Aerospace and Defense Accreditation Program (NADCAP).
Continually increasing its capital investment in cutting-edge technology is a significant aspect of the Precision Aerospace strategy. New equipment purchases are based on in-coming work loads, but also on how the technology can streamline production operations.
“Getting into 5-axis technology, for example, has allowed us to reduce part cycle times, increase throughput, and boost quality for both new and existing jobs,” said Bill Hoyer, president of Precision Aerospace. “Conversely, we incorporated processes such as laser part marking, non-destructive testing, pressure testing and electromechanical assembly — not for any specific job, but to simply broaden our capabilities and expand what we can offer customers.”
The shop’s job contracts are longterm, usually up to 60 months, and often of the “blue sky” type. As long as the customer is satisfied, the skies are blue, and the shop keeps getting the job renewed.
• Precision Aerospace Corp. Grand Rapids, Mich. www.precision-aerospace.com
• Number of employees — 135
• 2009 sales — $21 million
• Markets served: Aerospace and defense
Job releases occur at about 30 pieces per month, some as much as 2,000 per month or as few as two or three per month. Most parts are made from aluminum, stainless and exotic metals such as titanium, Inconel, and Waspalloy. And, since most jobs involve families of parts, Precision Aerospace relies heavily on single-piece flow manufacturing through machining cells that support entire part families.
Several different types of machines, both high-end and standard models, make up a cell at Precision Aerospace. Some parts may require a five-machine cell, while others only a two-machine cell. And because most of the jobs are long-running, cells don’t change much.
To support its cells, the shop has strategically located what it refers to as “standalone service centers.” These centers perform operations that are not conducive to a cellular environment, such as lapping, deburring, EDM and welding.
Hoyer said that it takes an array of different machines to handle the shop’s different jobs and materials. Its shop floor houses vertical machines from Haas, horizontals from Kitamura, 5-axis machines from DMG, and turning machines from Hardinge, just to name a few.
“Our philosophy is that we need a cadre of high-end machines to satisfy the high-end work we do. But conversely, we want to run our less complex parts on less complex machines,” he said.
Most parts at Precision Aerospace fall into the 12-in.-cube range, but some may measure up into the 32-in.- cube range. The shop machines its parts from castings or raw billets, though it much prefers to work from billets.
“I am huge proponent of convincing customers to go the billet route if possible,” said Hoyer. “Billets eliminate me having to deal with a castings supplier, latent defects not found until after a part has been machined, and with a bunch of inventory. Billets help reduce part prices, and I pass the savings on to customers, especially in the case of aluminum billets. And, if a part feature needs to change, a whole new casting doesn’t have to be produced.”
|”Orphan” jobs, those that don’t run on a regular basis, are machined in “orphan” cells at Precision Aerospace. |
The shop runs parts one of two ways, through cellular manufacturing or through what it refers to as the orphanage, which are cells for “orphan” jobs. Those are products/parts that don’t run on a regular basis.
For increased capacity, Precision Aerospace often machines jobs using more than one cell. The parts may not really match up with the cell, but the shop will, for instance, load the cell and run the roughing operations for all the parts overnight and unattended. Then, in the morning, the finishing work will be completed.
Certain jobs are dedicated to certain cells, but in between these jobs, the shop runs part operations that wouldn’t ordinarily be assigned to that particular cell. After the lights-out operations are completed, the part returns to its dedicated cell for the rest of its processing.
In any given month, as many as 1,800 different jobs can move through Precision Aerospace. To schedule and manage part flow, the shop relies on a JobBoss ERP system. Internal metrics such as defect levels (PPMs), part quality, safety efficiencies and indirect charge time are tracked also. Department leaders oversee scheduling of multiple cells and are there to solve any problems that may arise.
Quality control is mandatory at Precision Aerospace: the shop has nine CMMs and conducts a lot of inprocess inspection. Machinists check parts during manufacturing according to a sampling plan, and some orders are 100-percent inspected. The shop also has a Level 3 non-destructive tester on staff.
To keep up with the latest manufacturing and machining techniques, the shop sends machinists and engineers out for training, usually at an equipment supplier’s facility. According to Hoyer, in the past three business quarters, the shop has conducted 47 training events, some entailing leadership skills and cross training.
Machinists at Precision Aerospace set up and run the shop’s machining cells. There are three levels of machinists based on skills. The highest level, level three, involves more set-up skills than levels one and two.
Level two machinists can do some set-up, while those in level one basically run production and work on first shift because there is more support for them. Level three machinists, on the other hand, can be used on the weekends because they are more selfsufficient. Fortunately, level one and level two machinists can improve their skills through training and advance to level three standing.