• Powdered material is fused together in layers using a laser
• The powders need fine grains and thermo-plastic properties so that it becomes viscous, flows, then solidifies quickly.
• invented in 1986 by Carl Deckard
• marketed by DTM corp. (Sinterstation 2000)
• The process uses a heated chamber (near the powder melting temperature)
• The product is split into slices from the .STL file and created one layer at a time by spreading layers of powder, sintering the powder with a CO2 laser, then adding new layers of powder and sintering until done.
• When done the part is inside a cake of powder, and putty knives and spatulas are used to remove the loose powder
• Supports not needed as the unsintered powder supports overhangs/etc.
• slow cooling of the parts can prevent distortion due to internal stresses.
• The laser is about 50W infrared (about 10000nm) This power level is much higher than stereolithography
• Optics and x-y scanner are similar to SL
• the process chamber runs hot to decrease the power required from the laser, and reduce thermal shrinkage that would be caused by a difference in operation and cooling temperatures.
• The hot chamber is filled with nitrogen (98% approx.) to reduce oxidation of the powder.
• rate of production is about 0.5-1” per hour
- wide varieties of materials: wax for investment casting; polymers/nylon for assembly prototypes
- reduced distortion from stresses
- produce parts simultaneously
- rough surface finish (“stair step effect”)
- the first layers may require a base anchor to reduce thermal effects (e.g. curl)
- material changes require cleaning of machine
• DTM markets the Sinterstation 2000 for $250,000(US) to $497,000(US) depending upon the selection of 1, 2, or 3 materials (investment casting wax, nylon, or polycarbonate). The Sinterstation 2500 starts at $400,000
• Development is being done on,
- high power lasers for metal powders/etc.
• Selected specifications for a Sinterstation 2000 are given below,
