RP information request
From:
Jake Tucker (Battelle Pacific Northwest Laboratories)
Date:
Friday, July 22, 1994
From: Jake Tucker (Battelle Pacific Northwest Laboratories)
To: RP-ML
Date: Friday, July 22, 1994
Subject: RP information request
To Whom It May Concern,
I am currently conducting a "state-of-the-art" analysis of Rapid Prototyping/Solid Freeform
Fabrication (RP/SFF) technologies at the Pacific Northwest Labs (PNL). (By RP I mean those
technologies which build-up 3D objects from CAD solid models in a laminate fashion.)
PNL is a DOE lab and has been chartered with using its technology base to support industry. PNL has 3 primary interests in pursuing the "state-of-the- art" in RP: 1) procure current RP technology for
support of regional manufacturing; 2) "off-the-shelf" technology infusion into current process
development efforts; and 3) new process development. Potential "sponsors and/or partners" have been identified at each level of interest. To pursue these interests, we hope to identify current "gaps" in the technology by defining the "state-of-the-art" and comparing current capabilities with demands of future applications. We are interested in any collaboration which would speed us along. In specific, we have identified roughly 19 commercial RP vendors worldwide and would be interested in collaborating about the capabilities of these processes (e.g. SLA, SLS, etc.). If anyone has specific information concerning the capabilities of any particular RP technology I would be interested in discussing these matters further. Below is a list of parameteres, along with definitions, that we have compiled to compare diferent RP technologies. I would especially appreciate any direct information that addresses these parameters.My e:mail address is:
Thanks,
Jake Tucker
e-mail: jc_tucker@pnl.gov
RAPID PROTOTYPING PARAMETERS
Rapid prototyping parameters can be grouped into three major categories:
Equipment Parameters
Dimensional Parameters
Material Parameters
Equipment parameters captures the overall performance of the equipment in terms of cost, work
envelop, etc. Dimensional parameters capture the tolerances, surface finish, etc. associated with
fabricated shapes. Finally, the material parameters capture material properties. Parameter definitions are provided in the following sections.
EQUIPMENT PARAMETER
1. BUILD SPEED
This refers to the speed or rate of shape fabrication. Two measures are important here:
Scan velocity or volume/sec: scan speed x cross section of the voxel geometry or thickness of material being added to the shape.
Overall build speed: approximate build-time for a shape nearing the maximum work envelop of the
rapid prototyping apparatus.
The first measure capture the speed of the material deposit cycle. The second measure captures this
time as well as the time between the material deposit cycle (material preparation time,
positioning/alignment time, etc.).
EQUIPMENT PARAMETER
2. COST
The primary cost is the initial equipment cost. The next important cost is the cost of the prototyping
material by volume. The third and final cost category is any information that might provide maintenance
cost estimates (i.e., are there service agreements?).
EQUIPMENT PARAMETER
3. WORK ENVELOP
This refers to the maximum size of the fabricated shape which the rapid prototyping process is capable of producing.
EQUIPMENT PARAMETER
4. SPECIAL TOOLING REQUIREMENTS
This identifies any special tooling requirements required of the rapid prototyping process. One
example is special supports needed to keep the object from falling over during the build process.
EQUIPMENT PARAMETER
5. ENERGY REQUIREMENTS
This is a measure of the energy per unit volume (specific energy or horsepower) of the material
produced by the process. This information seeks to establish which process is most energy efficient.
EQUIPMENT PARAMETER
6. EQUIPMENT FOOTPRINT
This refers to the size of the equipment and support utilities required. This information seeks to
capture how portable the equipment is and how much infrastructure is required to support it.
EQUIPMENT PARAMETER
7. ENVIRONMENTAL TOXICITY
This seeks to capture any information regarding by-products and/or waste streams generated by the
rapid prototyping process.
EQUIPMENT PARAMETER
8. RECYCLABILITY/WASTE OF MATERIALS
This parameter is related to the previous parameter, and seeks to identify if the raw material can be
recycled or re-used by the process (e.g., unused powder can be reused).
EQUIPMENT PARAMETER
9. DOES IT REQUIRE/PROVIDE MICROSTRUCTURAL CONTROL?
(YES/NO, IF YES - DESCRIBE)
This captures if the process can control the microstructure of the shape being formed. (e.g., can we
control grain size in metals, can we control where we place two different materials inside a single shape,
etc.)
DIMENSIONAL PARAMETER
1. DIMENSIONAL ACCURACY
This is measured by percent accuracy.
Percent accuracy = tolerance/dimension
It can also be estimated by dividing quoted accuracy by dimensions of work volume. This is the hardest
metric to find. We may need to ask for accuracies in the XY plane vs. accuracies in the Z-axis.
DIMENSIONAL PARAMETER
2. SURFACE FINISH OF PARTS AND ASSOCIATED BUILD PARAMETERS
This measures the surface finish of the part produced. As this may vary according to build speed,
capturing build parameter information for any given surface finish is important.
DIMENSIONAL PARAMETER
3. SECONDARY PROCESSING REQUIREMENTS
This identifies any secondary processing requirements, such as cleaning, post-curing, polishing, etc.
MATERIAL PARAMETER
1. FABRICATION MATERIAL
Is the prototyping material a polymer, metal, ceramic, composite, etc.? What specific material type or
designation is it?
MATERIAL PARAMETER
2. MECHANICAL PROPERTIES
This captures the mechanical properties of the material as measured by the tensile strength, impact
strength, Young's modulus, and hardness.
MATERIAL PARAMETER
3. PART DENSITY
This applies largely to the powder processes. Measures include percent base material versus bonding material, and/or functional density/porosity of the part after debinding and after sintering.
MATERIAL PARAMETER
4. IS THERE PROPERTY ANISTROPY?
This seeks to identify if the finished shaped has uniform material properties, resulting from the
laminate nature of the particular rapid prototyping process being used. Typically, properties (tolerances, mechanical properties, surface finishes, etc. are worse in the Z-axis vs the XY plane. Measures for this include dividing the Z-axis parameter by the value for that parameter in the XY plane.
MATERIAL PARAMETER
5. THERMAL PROPERTIES
This captures the thermal properties of the material in the finished shape. Thermal measures include
the melting point, thermal conductivity, and coefficient of expansion.
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