Rapid Methods Taking Flight

Profit and loss, and the potential for success, depends on timeliness vs. hitting budget.New and current products with revision are now manufactured more accurately, in dramatically less time, and at a reduced cost compared to the normal evolution of new designs prior to 2000. It has evolved into a reliable, robust method that most companies embrace and depend on, and the staff at Clinkenbeard have embraced these new processes and moved them forward with continuing innovations.

Depending on your product material and complexity, having a source that specializes in SLA, SLS, or similar, may work very well. For companies that require metal sand castings or bar stock metal parts, going to a supplier with a broader range of in-house capabilities is usually beneficial. Having suppliers with multiple in-house resources reduces risk and provides greater control of schedules. If you produce a complex product, this may require 5-axis capabilities, CMM inspection, and/or more.

An ideal supplier has capabilities to become involved at the concept level and can continue to provide product through the mockup, prototype, and pre-production stages. This allows for one source, intimate contact with engineering and procurement through the whole development process, and allows for a single purchase order to be placed. A supplier with the needed certifications such as AS9100 and International Traffic in Arms Regulations (ITAR) will also be able to fit into the low volume category, with the ability to provide early parts while the production source becomes qualified. This is especially beneficial when there are startup issues to overcome.

Pump Case Study
The customer required two fully machined castings for concept and performance testing prior to investing in production tooling. The two parts were produced for $48,000. After the approval process was completed, exterior detail was completed and sand casting tooling was built for approximately $200,000. In cases such as pumps there is a high likelihood changes will be required. Doing the prototyping and testing saves significant time and money before going to the production tooling, where the changes will be an alteration of finished tooling or producing new tooling.

New Methods
There have been two newer developments for sand castings. Laser sintering or printing of sand with the sand grains held together with a binder material similar to the SLS process. The second is the Clinkenbeard Toolingless process, where cores and molds are produced from a bound sand block and configured via CNC machines. The latter allows for matching of sand and binders that are the same as those that will be used in the production process. This will reduce the risk of different outcomes in production after development is completed. These may be a valuable tool for the rapid production of metal castings in the development stages. We have also found the CNC method is a very valuable tool for the alteration of production sand cores when a production process needs to incorporate changes. It allows engineering changes to be proven prior to making expensive changes, or producing new, tooling. Depending on the configuration and changes this may provide a dramatic reduction in time and cost.

Certification
Aircraft components that reach the low volume or flight level need to be manufactured by a company that has AS9100 Quality Management Standard Certification and, in some cases and depending on the customer, ITAR Certification.

AS9100 is the quality management system standard specific to the aerospace industry. The current version, AS9100 Rev B published in 2004, includes the ISO 9001:2000 standard verbatim and adds supplementary requirements that apply to the aerospace industry.
The aircraft and aerospace industries have recognized AS9100 as a means for continually improving quality and on-time delivery within their supply chain. Most of the major aircraft engine manufacturers, such as General Electric’s Aircraft Engine division (GEAE), Boeing, Rolls-Royce Allison, and Pratt & Whitney, are requiring their suppliers to be certified to AS9100.

Administered by the U.S. Department of State’s Directorate of Defense Trade Controls (DDTC), under authority established by the Arms Export Control Act (AECA), ITAR, regulates the manufacture, export, and transfer of defense articles, information, and services. Companies receiving this certification demonstrate that they have knowledge and understanding to fully comply with the AECA and ITAR, as well as having corporate procedures and controls in place to ensure compliance.

Challenges to Using RP
Some of the weaknesses in the rapid prototyping industry are demonstrated when companies attempt to use their in-house processes for all products, whether they are good candidates for the process or not. Many times, this does not lead to the best outcome for the development process and may not reflect the production-intent product.

The best approach is to analyze each project and incorporate the best methods or processes to accomplish the required task and most likely replicate the finished production method. This may include CNC machining, the application of one of the sand machining or printing systems, and/or the use of an array of rapid prototyping processes that are currently available. Having a pattern shop in place is very helpful for using any or all of these processes, together, to make rapid metal castings.  

One of the criteria Clinkenbear implements is to consider what method can be applied that will most accurately replicate the actual production method. This is one of the things that led to the development of the Clinkenbeard Toolingless Process, since it was not available in the marketplace. It was the only way we could truly represent the follow-on production process via use of various sand grains and binder materials.

The Future
The next step the Clinkenbeard staff has taken is the application and current development of machining the sand shapes utilizing robots in place of CNC machines.

A Robotic Machining Feasibility Study with the Advanced Technology Institute (ATI) and the American Metalcasting Consortium resulted in utilizing the production of sand cores and molds via robot and CNC greatly reducing standard lead times for United States Department of Defense manufacturing jobs.

ATI (aticorp.org) currently leads several national collaborations that are developing advanced robotics capabilities and implementing both new and existing robotics technologies in response to US Department of Defense manufacturing challenges.

Doing prototyping and testing saves significant time and money before going to the production tooling.One national collaboration is with the American Metalcasting Consortium (AMC) amc.aticorp.org. The ATI-managed AMC partner companies, like Clinkenbeard, have used robotics technologies to support legacy weapon systems. Dramatically reducing lead times for legacy weapon systems parts is the key to the Defense Logistic Agency (dla.mil) partnership with the AMC. When working recently with the ATI-managed AMC, the Clinkenbeard Toolingless Process reduced the lead time for military cast spare parts from six to 12 months to six to 12 days. The results, according to ATI, also demonstrated that the Clinkenbeard Toolingless Process is capable of reducing capital investment by as much as 35%, reducing individual parts cost by up to 20% and improving cycle time by 25%.

This process and series of advancements are still in development with the hope of producing even more dramatic results. Two of the issue currently being addressed are:

1. Develop reliable approaches to utilize the rapid sand, toolingless methods for use on metal castings, which operate under very high pressures. In production there is a development cycle which takes place to develop a reliable gating and solidification system to obtain the required properties.
2. Producing superior quality parts, in a timely manner, without the luxury of the lengthy development cycle typically required to bring new product to market.

Providing this speed allows for more iterations and changes to be incorporated at the concept and development stages and not in the production mode, where costs will be much higher.

How will this rapid technology be accepted by quality departments in the production arena so these types of processes can be accepted as initial production or low volume production parts? With new product development cycles being greatly reduced, quality acceptance standards need to be addressed to find a method to develop acceptance of reliable rapid manufacturing and prototyping techniques. While these issues are significant, they need to be addressed and overcome to continue to advance in this area.

By Ron Gustafson
President
Clinkenbeard
Rockford, IL
clinkenbeard.com