Laser sintering use for bespoke dental prostheses

Written by: Tom Shelley | Published:

Restoration dental crown and bridge frameworks are now being built using Direct Metal Laser Sintering (DMLS)

. The technology has been developed by two German companies, Sirona Dental Systems and Electro Optical Systems (EOS).
Sirona’s process, called infiniDent, begins with the impression of the patient’s teeth being sent from the dental surgery to Sirona’s laboratory, where a plaster model is produced. A non-contact scanner creates a digital model of the teeth and the required framework is designed using CAD/CAM software.
Data is sent over the Internet to infiniDent, where the files are used to dive the laser in an EOS DMLS machine to fuse successive layers of cobalt chrome powder. Turnaround time is typically three working days from the receipt of data.

Dr Saliger, project manager at Sirona’s inifiniDent division, commented, “Industrial production of dental frameworks by DMLS is not only more cost-effective, but also provides consistently high quality.”

Cam-less cylinder head’s fast delivery
Valve actuators for a prototype cam-less cylinder head have recently been made by CRDM by investment casting and delivered to Houghton-Parkhouse in Milnthorpe, Cumbria, which is now trialling it.
Houghton-Parkhouse is noted for its transporters, especially those designed for livestock and horses, but also has a patented hydraulic timing and valve lifting system for engines. The cylinder head is about 9kg lighter and 85mm lower height than a conventional head and does away with the need for pressure lubrication. It also has positive opening and closing of the valves, which can be positioned optimally for engine function without requirements for compromise arising from cam shaft positioning or oil feed and scavenging.
CRDM, the Centre for Rapid Design and Manufacture in High Wycombe, delivered the 16 fully machined, investment cast valve actuators ahead of schedule. Houghton-Parkhouse expects eventually to be able to vary both valve lift and timing for both inlet and exhaust valves. The system is also expected to allow faster engine speeds.


New scanner is hand held
A hand held, mobile scanner has been introduced to the UK by Unimatic Engineers.
The Handyscan is pointed towards the object to be scanned, and moved about so that a self positioning cross hair sweeping laser is moved over the surface. This generates a stream of positional data, the initial value of which is used as a datum from which all other data is measured. Software constructs the data into a 3D scan or virtual model of the object, aided by a surface optimisation algorithm.
The digitising software is said to be easy to learn and to integrate with existing systems through its Windows compatibility and ability to export files in standard formats such as Geomagic Studio and Qualify. Other applications planned for imminent integration include Polyworks, Catia V5, Prelude Inspection and Rapidform.
Unimatic Engineers

Notebooks speeded by new system
Dell has just purchased Stratasys’ 6000th system – an FDM Vantage SE - in order the help develop early and speculative prototype of parts and subsystems for notebook computers, computers and enterprise systems.
The company has used a previous FDM machine for many years and development group’s senior engineering manager, Andrew Moore, said: “We didn’t need to be convinced of its accuracy. We proved it to ourselves previously. We’ve been satisfied with the original FDM system, so purchasing a second one was an easy decision.”
The expanded suite of available materials was one reason for purchase. Dell also liked the machine’s large build envelope, which allowed it “to build almost any size plastic part within our designs in a single build”.


Motion software evaluates high power circuit breakers
Toshiba Power Systems is using LMS Virtual Lab Motion to study mechanisms in high voltage circuit breakers that blow in insulating gas in order to shut down transmission.
“Creating detailed multibody simulation models of our circuit breakers in LMS Virtual Lab Motion allows us to carefully analyse the functioning of these mechanisms under high speed conditions and to optimize the critical interaction between key components,” explained Mr Ohda of the Power Industrial System R&D Center at Toshiba. “With Virtual Lab, we are able to virtually test new designs on all possible worst case scenarios, and to make sure that in any case the electric power is completely shut down inside the power circuit breaker.”


Cylinder models created online
Parker Hannifin has developed a free software package to create 3D models of hydraulic cylinders, which is available either online or on a CD-ROM.
The product covers all products in the HMI, HMD and 2H ranges of 210 bar inch and metric tie rod cylinders.
To use the software, designers launch the package and from the range listed, select the 2D and 3D formats they wish to use. Next the range of cylinders is selected in a browser window and details of the specifications entered. Accessories can be added at this stage.
The software quickly generates a 3D model of the cylinder, which is presented on screen for verification, as well as a bill of material for the cylinder and a detailed specification that can be printed for future reference. When the designer is satisfied, the model can be saved or transferred directly to the 3D CAD package if the CD version of the program is being used, or download if the model was generated online.
The web URL is www.parker.com/euro_cylinder/v4/services/3dcad.asp.



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