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Roncelli ‘Conducts’ Quality Machining on Electric and Aerospace Parts

Experts in plastic machining, Roncelli Plastics combines its vision, expertise, manufacturing capabilities and total quality management to machine plastic components for the semi-conductor, aerospace, defense, electronic and medical industries.

By Chad Sypkens

After 31 years of business, Monrovia-CA-based Roncelli
Roncelli machines numerous plastic parts used in the C-17 Globemaster III, the newest, most flexible cargo aircraft to enter the airlift force. The C-17 is capable of rapid strategic delivery of troops and all types of cargo to main operating bases or directly to forward bases in the deployment area.
Plastics finds itself in the middle of some major plastic industries, including semi-conductor, aerospace, electronic and medical. On any given day, nearly 80 jobs will be shipped to its diverse clientele.

Eighty employees work two shifts (6:00 AM - 2:00 PM and 2:00 PM - 10:30 PM) at the 40,000-square-foot job shop facility, where they churn out close tolerance machined plastic parts held under strict standards.

“We pride ourselves in a clean shop that makes high quality products. It is good for the morale of all the employees to work in an atmosphere like this,” says Roncelli President, Jeff Tenney, who has been with the company for over 20 years. “Our credo is ‘Delivering Quality On Time.’ It is identifiable to every one of our employees ,and our customers too. It really sums up our goals.”

One of the key factors to Roncelli Plastics delivering quality products is that its employees have been empowered with the skills and tools needed to make a quality part. The employee base has a cumulative total of over 500 years of plastics experience.

“Our company is able to provide a high quality of service because our employees are the best,” says Tenney. “They are highly trained and very committed to their jobs and for that reason alone we are able to succeed. They make it happen.”

They “make it happen” by utilizing a wide variety of machines and plastic materials, from A to Z (acrylic to Zytel) to service the strict tolerance needs of the semiconductor and aerospace.

Its fabricating operations include Gibbs and Surfcam CAD-CAM programming systems, Miyano and Hass CNC lathes, four Kennard CNC drilli0ng/routing machines, a Hendrick panel saw, Thermwood CNC router and eight CNC machining centers (two Miyano, three Fadal, three Okuma), to go along with 40 pieces of conventional equipment such as lathes, drills, mills, saws, thermal forming, screw machining, die cutting and stamping machines.

Semi-Conductor Industry Adds Big Change to Roncelli

Shown is a 9-inch diameter gray PVC Type 1 rod which has been machined into a housing for International Transducer Corp.
“Our growth in the semiconductor industry has been one of the biggest changes for us,” says Tenney. “This industry uses a lot of machined plastic parts and components, very close tolerance parts, that demand ultra-high quality. Demands for ±0.0005-inch tolerance are very common. Some of these plastic materials inherently are not very stable and need annealing steps necessary to stress relieve the materials so they will be able to hold the tolerances.”

For International Transducer Corp., Santa Barbara, CA, Roncelli machined a housing for an underwater electroacoustic transducer to convert electrical energy into acoustic energy or vice versa. Sonar detection, underwater communications and ocean depth measurement are just a few of the typical applications.

Roncelli’s process to create this part began with a 9-inch-diameter gray PVC Type 1 rod, which is cut into 9-inch long pieces on a Do-All horizontal bandsaw. The part is then placed in the Despatch forced air circulating oven where it undergoes a 16-hour annealing process.

A Fadal CNC mill then rough machines the oversized part before another trip back to the annealing oven. Once the part is out of the oven for the second time, the finish machining takes place on a Okuma CNC mill, where the part gets bored, milled and drilled. O-ring grooves are also incorporated at this point.

The part is then sent to the “conventional” end of the shop where the components will be tapped and Helicoil wire inserts are installed. The deburring process is then performed to make sure all the edges are smooth and the part is ready for delivery.

After 12 In-Process inspections, the final inspection will be the last step before it's bubble wrapped and awaits the customer's delivery schedule.

Defensive’ Diversification

A diversified plastics machinist must know each material’s peculiarities a
Roncelli’s Thermwood CNC router has added to its diversification allowing for the machining of larger sheets of plastic.
nd what needs to be done with it before it can be turned over to the customer. How stable it is? Does it need oven drying? How much? At what temperature? For how long? How about annealing...stress relief? In some cases, certain materials need pre-machine, in-process and post-machine annealing to keep them relaxed, stable and in tolerance.

Roncelli Plastics’ diversity extends into the defense industries. It machines plastic parts for military helicopters, satellites and the space shuttle to name a few, working with the largest companies in the aerospace and defense industries.

The Boeing C-17 Globemaster III, the newest, most flexible cargo aircraft to enter the airlift force, is designed to carry large combat equipment and troops across international distances anywhere in the world.

“We make a variety of items that are used in the C-17, in upwards of 500 different part numbers,” says Tenney. “Imagine how many different machined parts are in that aircraft out of a wide range of materials. Some of what we make include liners from glass phenolic laminates, clamps and fairleads from wear-resistant nylon and canvas phenolic and seals made from rubber.”

Roncelli also machines clamp assemblies to keep the hydraulic hoses from rubbing together and abrading as well as teflon rub plates for where doors open and close and anti-skid flooring.

Roncelli also produced commercial aircraft parts for McDonnell Douglas prior to the company being purchased by Boeing. Tenney says the good supplier relationship and trust Roncelli built with McDonnell Douglas carried over to Boeing and Roncelli now has plans to make parts for over 120 C-17 aircrafts.

“You hear a lot about military readiness and this aircraft definitely fits the bill,” says Tenney. “I was able to visit the plant in Long Beach earlier in the year and was given a first-hand look at our products after assembly. What a massive aircraft.”

Satellites & Medical Equipment

Roncelli has machined a bracket for Hughes Space and Communications made out of GE’s 30 percent glass filled Ultem 2300 that is used on a solar array panel for one of its satellites. It holds a pivot, which Roncelli also makes, and is attached to a mast to collect solar energy for the satellite to operate.

The bracket started as a 2-inch thick sheet. Using the Okuma CNC machining center, tolerances were to be at ±0.0005-inch thicknesses, very common when dealing with such a part. “We had five different setups for the part which involved very close, tight tolerances,” says Tenney.

Hughes is one of the largest satellite manufacturers in the world and produces many different types of items for commercial and military use which incorporate a lot of plastic parts. Tenney estimated that Roncelli probably makes roughly 200 different parts for Hughes’ various satellites.

“The medical industry is also a huge field for us.” says Tenney. “We have made parts that are used in the calibration of X-ray machines, pacemakers and equipment used for drug and blood analyzation.”

One specific application Roncelli does in the medical field is for a medical device called the Lithotripter, which has components made out of DuPont Delrin acetal and GE Lexan polycarbonate, says Tenney.

The Lithotripter is used for dissolving kidney stones with sound waves, a non-evasive way to get rid of kidney stones. They pound them with sound waves and break them into tiny pieces.

Tracking the Flow

“In the shop is a well organized flow that keeps it manageable, says David Nuckolls, purchasing manager, who has worked at Roncelli for seven years. “It’s tough to manage 500 jobs and maintain a 99 percent delivery rating, but that is what we do. The bar coding, the routing on the travelers and every employee knowing when a job has to be finished is what it’s all about. We don’t see all 500 jobs at once, but they are somewhere in the system. Sometimes it amazes me how we manage to maintain that delivery rating with so much going on, but we do.”

“The data collection system we use in our shop keeps track of every minute that someone is working on a job so when we are finished we have a full accounting of how much that job cost,” adds Tenney.

“When you really get down to it, we sell time. We are a service company that sells time on our machines, so its extremely important to keep track of how much time we spend working on particular jobs,” says Tenney. “We don’t have a product line, we don’t do design, we build everything to our customers specifications and when we quote jobs we try to estimate how much time its going to take to make the job.

Every operation at Roncelli has a bar code and a tag and can be tracked down to the precise minute and how long it took for every job. “We use JobBoss software, which we have used since 1992. Our database is the largest they have ever seen. Our SPC (Statistical Process Control) chart makes each machinist stop and measure every so many parts to make sure the quality and precision does not slip.”

Roncelli’s SurfCam and Gibbs, which are different CAD/CAM systems that run in tandem, can be used for programming any part that it makes. “We found that as we grew and added equipment, that we needed a second system,” says Tenney. “It was taking too long to program everything through one system. Computer problems are inevitable and they go down, which would put us behind. Now it gives us a lot more comfort having a second system always running in case one goes down.”

Supplier of the Year Award

Roncelli’s success in production tracking helped it to win the Hughes Missile Systems, Supplier of the Year award two years in a row (1995-96). “Hughes Missile Systems has facilities all over the country with 4,000 suppliers in their supplier base, so to win that award was extremely prestigious,” says Tenney.

Buyers make nominations to a committee and look at each company and case individually. The requirements are quite difficult in order to even be considered for supplier of the year, he adds. “In 1996, we had the best supplier rating out of all 4,000 suppliers in their system,” says Tenney. “That was delivering a lot of parts on-time and without any quality defects. We have also won other supplier of the year awards and have been approved as certified suppliers for other companies which means that they don’t inspect our parts at all in a lot of cases. They have such a high level of confidence in our quality that our parts go straight into the line.

“Alliances are the secret to our success,” says Tenney. “Customer satisfaction is our first priority. We perform under rigorous quality control standards by working with our customers at the preliminary design stages striving toward the goal of zero defects. From inspection of incoming raw materials, to first article inspection of each operation, to SPC in-process inspection and final inspection of each part before shipment, our quality control department ensures a high quality product.”

Backplanes Spur Roncelli’s Start

In 1969 owner Gino Roncelli started the company by making all types of plastic machined parts, its bread and butter being backplanes for Burroughs Computer Co.

The backplanes were made from a single layer of copper clad laminate, a glass epoxy sheet 1/8 inch thick with a layer of copper on one side for conductivity. After machining, plating and silk screening, Burroughs would receive them ready to assemble. They were used as grounding boards in old computers back when you needed a computer the size of a bedroom to do a pretty simple function.

“That is what got the company in business up until about the early to mid-80s, at which point the technology changed and Burroughs became Unisys,” says Roncelli President Jeff Tenney. “The boards were phased out and we focused on other jobs, other areas. We still do a variety of machined and die cut parts for Unisys today, but not very much,” says Tenney. “They are our oldest customer. At one point in the 70s they were probably half of our total sales. Now Unisys represents less then 1 percent.”

The main reason is Roncelli has become so diversified in so many different industries and it doesn’t throw all their eggs in one basket. “I would probably say that our top 10 accounts combined only amount to 50 percent of our business,” says David Nuckolls, purchasing manager. “Regardless of the size of the company, whether you’re Boeing or a startup .com company or a guy in his garage, our customers will always come first and receive the same service as anyone else.”

For more information on Roncelli Plastics, go to

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Plastics Machining & Fabricating
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