The advent of private spacecraft development companies has transformed the manufacturing environment for rocket and satellite components. Previously, government organizations, including NASA and the United States Department of Defense, sponsored most of the space production. Now, the profitable entrepreneurs behind Blue Origin, SpaceX and Virgin Galactic are driving the next generation of space technology advancement.
The growing private space business constitutes a new industry with new relationships, new requirements and new opportunities for manufacturers.
Gray Manufacturing Technologies is a supplier who benefits. The NC-based Denver store has leveraged these opportunities with its application of advanced machining and, most importantly, automation technology to meet the growing demands of the space flight industry.
Gray’s product mix is high and individual part volumes are low. “The vast majority of our business is aerospace [aircraft] or space and satellite components, ”said Gary Holcomb, president and CEO of Compass Precision, Gray’s parent company. “Most of the works are five to 10 pieces and most are different from the previous works. They are not exactly prototypes, but they are complicated parts in very small volumes and we ship up to 100 jobs per month. “
As spacecraft companies constantly modify and improve their technologies, engineering changes are frequent. “We can make five parts for a customer, so they can order five more, but with different sizes,” explained Holcomb. “There are frequent change notices and a lot of shifts in and out of production schedules. We may receive six orders due in three months, but a week later they need two orders first, while another two will be moved out of the production schedule. “
Automation has proven to be a key component of Gray’s approach to space and satellite product processing services. “When we first talked about automation, we were looking at it from a capacity issue,” said Evan Grose, Gray’s head of manufacturing operations. “We didn’t have the space to keep loading the same part over and over on the same pallet.”
To increase spindle uptime and production flexibility, the shop acquired two five-axis MILL E 700 U machining centers from GF Machining Solutions LLC, Lincolnshire, Illinois, located in a cell that includes a modular robot System 3R Transformer together with a 12- pallet loading station. The robot travels on a rail to move pallets in and out of the machines, as well as to load and unload pallets offline at the loading station. These combined capabilities provide extended lights-out operations to Gray.
GF Machining Solutions’ automation allows Gray to efficiently manage his low volume / high mix workload. “The flexibility of the equipment is very important,” said Holcomb. “During the day we focus our resources on making one, two or five piece works for space clients. So, before we go home, we take the non-space work, basically larger volume aerospace work that is already scheduled, and we do it at night. We use what the MILL E 700 offers in terms of programmability for the complicated and very small batches during the day, then use the automation capabilities for the slightly higher volume and non-spatial work we do without light.
Unlike typical multi-pallet systems which can limit the amount of unattended production to anything that is loaded onto the pallets before the lights are turned off, the Transformer robotic system removes the pallets with completed work from the machine and replaces them with the loaded pallets. It then unloads and reloads the pieces on the inactive pallets while the machining continues uninterrupted. “We refer to it as automation for automation,” said Holcomb.
For unattended operation, the tool break detection is set in the machining program. If a tool breaks, the machine stops and changes tool. The MILL E 700 U machines have more than enough tool storage space to support Gray’s extended unattended operation, with tool wear compensation and replacement of redundant tools called into the program as needed.
“We have continued along the automation path due to the increasing complexity of our work and because it is more difficult to find employees with the right technical skills,” explained Holcomb. “We chose the robust Transformer robot over an articulated robot because the machining center’s ability to perform complex movements makes the use of a fully articulated robot superfluous,” he added.
The alternative to the robotic automation system would be more machines, said Holcomb, “and, depending on how many machines are in use, even more people, because we can’t expect one operator to manage seven or eight machines. Based on our current order levels and without robotics, we would need at least three more machines for a total of five and two more people. And at this point in our business, it is more difficult to find the people than to acquire the machines ”.
Although part volumes are currently low, higher volumes are expected which will allow the shop to take full advantage of the capabilities of the Mikron MILL five-axis machines and robotic pallet system. “Higher volumes in this case don’t mean millions of pieces,” said Holcomb, “We need a few dozen pieces instead of five to 10.”
Automation will become more important as the commercial spacecraft business grows and matures. According to Holcomb, the store is experiencing a higher-volume migration of parts that he has already planned. This means less programming demand and a greater demand for extended machine times provided by GF Machining Solutions’ automated cell.
Holcomb went on to say that machining speed, in addition to automation, is critical to success in manufacturing aerospace and space vehicle components, most of which require machining complicated aluminum parts at high rpm.
In addition to the two machines in the automated cell, Gray has a Mikron MILL E 500 U and a MILL S 600 with seven-pallet carousels. One machine has a 36,000 rpm spindle, the other 20,000 rpm.
By contributing to the shop’s responsiveness and efficiency, Gray is committed to a “one-time setup” approach to machining, according to Jerry Soots, former CEO and president of Gray Manufacturing and now a consultant. To achieve this manufacturing goal on a five-axis milling machine, Soots explained, Gray leaves the tabs strategically placed 0.005 “to 0.010” on the blanks and locks the job into a dovetail device that allows machining of all characteristics of the part.
The fixture provides a large distance between the bottom of the part and the machine. For this reason, the shop can reach the underlying features and work from any angle. Once the piece is finished, it is measured on a CMM; when it is compliant, they process the cards.
The burgeoning private space manufacturing industry is forging new relationships between spacecraft companies and their suppliers. Thirty years ago, suppliers had to present their capabilities to aerospace companies, which generally weren’t actively looking for suppliers. Unless a component was part of a new aviation program, changes to the design of the parts were rare.
“Today, commercial space companies are doing everything on the fly,” said Holcomb, “it’s a completely different mindset. They are aggressively looking for qualified suppliers who can be responsive to the constant stream of new products and constant design changes.
“The latest ISO and AS 9100D certifications are the minimum qualifications. You have to be very technically competent. You need to be able to make these challenging parts in relatively low volume, sometimes aluminum, sometimes more difficult materials. You have to be agile enough to satisfy the fluidity they need in production planning. Our five-axis milling machines and automation from GF Machining Solutions play a key role in meeting all of these needs. “
For information on gray manufacturing technologies, visit gray-mfg.com or call 704-489-2206. For information on GF Machining Solutions, visit www.gfms.com or call 800-282-1336.