Delcam’s PartMaker CAM software has been part of a new philosophy at dental manufacturer Sterngold Dental LLC. The addition of the software and new Citizen Swiss-type lathes has seen the company move from outsourcing the majority of its manufacturing work to undertaking almost all of its production in-house at its Attleboro, Massachusetts, headquarters.

"In an effort for continuous improvement and to achieve optimum efficiency, Sterngold embarked on a programme two years ago to expand our internal manufacturing capabilities,” explained Director of Operations, Lee Clermont and Senior Engineer, Bruce Seavey.  "Until that point, we relied on several outside vendors.  Another big benefit in shifting to in-house manufacturing is the ability to do rapid prototyping and so bring new products to market more quickly.”

"Lead time has also played a factor in our decisions,” said Mr. Clermont.  "Some of our parts require small manufacturing runs and having the ability to schedule our own jobs allows for more flexible production.”

The management realised that it needed new staff before it could make the change to in-house production and so hired designer and engineer Bruce Seavey and machinist John Souza.  "These appointments have been crucial to our new approach,” said Mr. Clermont.  "They are both experienced in their field, of course, but the main benefit has been the way in which they work together to develop products that not only meet our customers’ needs but that can also be manufactured cost-effectively.”

Sterngold installed the first of its new machines early in 2006.  Mr. Clermont and Mr. Seavey chose Citizen equipment because they believed it would allow faster set-ups, an essential requirement given the number of small runs being produced.  The second machine followed in November, and a third one last year.  The company’s current plan is to continually ramp up with additional equipment each year as production increases.  External machining is now down to around 10% of total production.

The main components being machined are the ERA? implants and the ERA family of resilient dental attachments.  "These are used to stabilize loose-fitting dentures,” explained Mr. Seavey.  "Creating the complex angles in our components would be extremely difficult with manual programming, even if multiple set-ups were used.  In contrast, with PartMaker it is easy both to create a program to make the parts in one operation and to run a simulation to check what will actually happen on the machine.” 

"With Part Maker we can maximize the efficiency of our programs, greatly reducing cycle times.  With the Citizens’ capabilities and some specialized tooling and holders, we can machine the part completely in about four minutes,” said Mr Souza.  "Using conventional methods, we would need two machines and a special fixture, with the cycle time probably approaching four minutes on each machine.” 

As well as being small and having to be machined to tight tolerances, the design of the ERA? dental implants makes them difficult to hold in the machine.  "On these particular parts, we are holding onto it in the back spindle by .012 inches so toolpaths tend to be as little as one or two thousandths of an inch.  That’s a lot of tool paths to calculate without any software,” according to Mr. Souza.  "There are also features on some of our pieces, such as tapered form threads and threads that follow contours and radii, that are difficult enough to work out using the software, never mind manually.”

The ease of use of the PartMaker software enabled Sterngold to ramp up production on the new machine more quickly than expected.  "We scheduled three jobs to be completed in the first month after installation but completed them all in a week,” remembered Mr. Souza.

Another big benefit of the software is the reduction in the time and difficulty of setting up the machines.  "Because of our short runs, we are usually setting up a different part on at least one machine every day,” explained Mr. Souza.  "By doing our planning and testing on the software, we can reduce the downtime between set-ups by at least 40%.”

"PartMaker has also allowed us to have our machine operators setting up our equipment for different parts,” he added.  "The software tells them which tools to load into the various stations on the machine.  The time needed to prove out the program is greatly reduced because most mistakes can be corrected before the program ever reaches the machine.”