Subtractive processes, often referred to as CNC machining, have not stood still in the rapid prototyping arena. Faster tool path generation is just one of the newer developments enabling machining to play a strong role in the rapid prototyping and direct digital manufacturing arena. Now, robotic machining has the potential to significantly affect the rapid casting arena, especially in the area of large castings. Tooling costs as well as lead times increase dramatically as parts get larger. The equipment needed to deal with the size and weight of extremely large parts becomes more rare and thus, more expensive. The larger the equipment used for these large parts, the slower it will operate due to its heavy physical characteristics. The most significant advantage that robotic machining seems to have is the fact that the robot moves independently of the work piece giving it the ability to feed as quickly on a large part as it does on a smaller, lighter part.

The US Department of Defense (DoD) has been seeking a way to reduce the cost of producing cast spare parts. The Advanced Technology Institute (ATI) currently leads several national collaborations that are developing advanced robotics capabilities and implementing both new and existing robotics technologies in response to the DoD’s need.

One collaboration is with the American Metalcasting Consortium (AMC). The ATI-managed AMC partner companies, like Clinkenbeard, are using robotics technologies to support legacy weapon systems; which could help meet the Defense Logistic Agency’s goal of dramatically shorter lead times for the production of legacy weapon systems parts. The patented Clinkenbeard® Toolingless Process proved that it could reduce lead times for military cast spare parts from six to twelve months to six to twelve days.

The results, according to ATI, also demonstrated that the Toolingless Process can reduce capital investment by as much as 35%, reduce individual parts cost by up to 20%, and improve cycle time by 25%.

Lead times often exceed a year because technical data may require reworking, including the development of a solid model of the part. But, even when a solid model is generated first, the Clinkenbeard process can supply a cast part in less than a month. The secret is computer-generated molds with no tooling.

The Toolingless Process consists of machining sand cores and molds, and is accurate. According to the company, this process can reduce the lead-time to obtain development castings by up to 90%. With this process, you can:

• eliminate the need for prototype tooling, depending on project requirements.
• make and test multiple design iterations during product development, from the simple to complex parts.
• reduce the cost of production tooling for one-of and small quantities.
• obtain accurate, prototype parts while large quantity tooling is made.
• eliminate tooling inventory.
• match exact production core materials and chemical levels so that prototype castings emulate production.
• incorporate engineering changes into high-volume production sand cores.

Clinkenbeard developed the sand machining process using CNC machining centers. By using robots with sand machining, company technicians can use the process on much larger molds and cores. Robotic technology will reduce the cost dramatically compared to the same expenditure for CNC machining centers.

Clinkenbeard
www.clinkenbeard.com

American Metal Consortium
http://amc.aticorp.org/

Defense Logistic Agency
www.dla.mil

Advanced Technology Institute (ATI)
www.aticorp.org