Organizing information: the MATERIALS TREE. The CES Software. Structured information for ABS* Unstructured information for ABS* DBs.

Transcription

1 The CES Software Organizing : the MATERIALS TREE Level st year students: Engineering, Materials Science, Design Level 2 2nd - 4th year students of Engineering and Materials Science and Design. Specialist DBs DBs Eco Eco design design Mil Mil handbook handbook 5 and and 7 7 Campus Campus and and IDES. IDES. Level 3 4th year, masters and research students of Engineering Materials and Design. Kingdom Materials Family Ceramics & glasses Metals & alloys Polymers & elastomers Hybrids Class Steels Cu-alloys Al-alloys Ti-alloys Ni-alloys Zn-alloys Member Attributes Density Density Mechanical Mechanical Thermal Thermal Electrical Electrical Optical Optical Corrosion Corrosion Structured Unstructured 64 materials 9 materials 296 materials A material record 75 processes 07 processes 233 processes ME Fall 2006 CES - ME Fall 2006 CES -2 Structured for ABS* Unstructured for ABS* Acrylonitrile-butadiene-styrene (ABS) - (CH2-CH-C6H4) n What is it? ABS (Acrylonitrile-butadiene-styrene ) is tough, resilient, and easily molded. It is usually opaque, although some grades can now be transparent, and it can be given vivid colors. ABS-PVC alloys are tougher than standard ABS and, in self-extinguishing grades, are General Properties Density Mg/m^3 Price US $/kg Mechanical Properties Young's Modulus GPa Elastic Limit 8-50 MPa Tensile Strength MPa Elongation 6-8 % Hardness - Vickers 6-5 HV Endurance Limit - 22 MPa Fracture Toughness MPa.m /2 Thermal Properties Max Service Temp K Thermal Expansion /K Specific Heat J/kg.K Thermal Conductivity W/m.K Electrical Properties Conductor or insulator? Optical Properties Transparent or opaque? insulator Opaque Corrosion and Wear Resistance Flammability Fresh Water Organic Solvents Oxidation at 500C Very Poor Sea Water Strong Acid Strong Alkalis UV Wear Poor + links to processes used for the casings of power tools. Design guidelines. ABS has the highest impact resistance of all polymers. It takes color well. Integral metallics are possible (as in GE Plastics' Magix.) ABS is UV resistant for outdoor application if stabilizers are added. It is hygroscopic (may need to be oven dried before thermoforming) and can be damaged by petroleum-based machining oils. ABS can be extruded, compression moulded or formed to sheet that is then vacuum thermoformed. It can be joined by ultrasonic or hot-plate welding, or bonded with polyester, epoxy, isocyanate or nitrile-phenolic adhesives. Technical notes. ABS is a terpolymer - one made by copolymerising 3 monomers: acrylonitrile, butadiene and syrene. The acrylonitrile gives thermal and chemical resistance, rubber-like butadiene gives ductility and strength, the styrene gives a glossy surface, ease of machining and a lower cost. In ASA, the butadiene component (which gives poor UV resistance) is replaced by an acrylic ester. Without the addition of butyl, ABS becomes, SAN - a similar material with lower impact resistance or toughness. It is the stiffest of the thermoplastics and has excellent resistance to acids, alkalis, salts and many solvents. Typical Uses. Safety helmets; camper tops; automotive instrument panels and other interior components; pipe fittings; home-security devices and housings for small appliances; communications equipment; business machines; plumbing hardware; automobile grilles; wheel covers; mirror housings; refrigerator liners; luggage shells; tote trays; mower shrouds; boat hulls; large components for recreational vehicles; weather seals; glass beading; refrigerator breaker strips; conduit; pipe for drain-waste-vent (DWV) systems. The environment. The acrylonitrile monomer is nasty stuff, almost as poisonous as cyanide. Once polymerized with styrene it becomes harmless. ABS is FDA compliant, can be recycled, and can be incinerated to recover the energy it contains. ME Fall 2006 CES -3 ME Fall 2006 CES -4

2 Organizing : the PROCESS TREE Structured for Injection molding Kingdom Processes Family Joining Shaping Surfacing Class Casting Deformation Molding Composite Powder Rapid prototyping Member Compression Rotation Injection RTM Blow Attributes Material Material Size Size Range Range Min. Min. section section Roughness Roughness Economic Economic batch batch A process record Structured Unstructured Physical Attributes Mass range kg Section thickness 4e e -3 m 7e -5 e-3m Roughness µm Surface roughness (A=v. smooth) A Process Characteristics Discrete Economic Attributes Economic batch size (units) e 4 e 6 Relative tooling cost very high Relative equipment cost high Labor intensity low Cost Modeling Relative cost index (per unit) * Parameters: Material Cost = 0USD/kg, Component Mass = kg, Batch Size = 000, Overhead Rate = 0USD/hr, Capital Write-off Time =.577e 8 s, Load Factor = 0.5 Capital cost *2e 4-4.5e 5 USD Material utilization fraction * Production rate (units) * /s Tooling cost *2000-2e 4 USD Tool life (units) *e 4 -e 6 Circular prismatic Non-circular prismatic Solid 3-D Hollow 3-D ME Fall 2006 CES -5 ME Fall 2006 CES -6 Unstructured about Injection Molding Unstructured about Injection Molding Design guidelines Injection molding is the best way to mass-produce small, precise, polymer components with complex shapes. The surface finish is good; texture and pattern can be easily altered in the tool, and fine detail reproduces well. Decorative labels can be molded onto the surface of the component (see Inmold Decoration). The only finishing operation is the removal of the sprue. Technical notes Most thermoplastics can be injection molded, although those with high melting temperatures (e.g. PTFE) are difficult. Thermoplastic-based composites (short fiber and particulate filled) can be processed providing the filler-loading is not too large. Large changes in section area are not recommended. Small re-entrant angles and complex shapes are possible, though some features (e.g. undercuts, screw threads, inserts) may result in increased tooling costs. The process may also be used with thermosets and elastomers. The most common equipment for molding thermoplastics is the reciprocating screw machine, shown schematically in the figure. Polymer granules are fed into a spiral press where they mix and soften to a dough-like consistency that can be forced through one or more channels ('sprues') into the die. The polymer solidifies under pressure and the component is then ejected. Typical uses Extremely varied. Housings, containers, covers, knobs, tool handles, plumbing fittings, lenses,. The economics Capital cost are medium to high, tooling costs are usually high - making injection molding economic only for large batch sizes. Production rate can be high particularly for small moldings. Multi-cavity molds are often used. Prototype moldings can be made using single cavity molds of cheaper materials. Typical products. Housings, containers, covers, knobs, tool handles, plumbing fittings, lenses. The environment Thermoplastic sprues can be recycled. Extraction fans may be required for volatile fumes. Significant dust exposures may occur in the formulation of the resins. Thermostatic controller malfunctions can be hazardous. ME Fall 2006 CES -7 ME Fall 2006 CES -8 2

3 Finding Finding with CES Handbooks, compilations (see Appendix D of The Text) Suppliers data sheets The Internet : Finding data using the EduPack Browse: locate candidate on MATERIALS or PROCESS TREE and double click, Search: enter name or word string name (trade-name, or application) 3 levels of data, with increasing content Level : 64 materials 73 processes Level 2: 9 materials 07 processes Level 3: 296 materials 233 processes Tables or compilation of data but no comparison or perspective Data table Toolbar Browse Select Search Print Search web Choose what you want to explore (materials, processes..) Materials Metals Polymers Ceramics Links Processes Casting Moulding Powder Data table Find what? Which table? ME Fall 2006 CES -9 ME Fall 2006 CES -0 Relationships, perspective and comparisons Bar- chart created with CES (Level) Data sheets do not allow comparison, perspective. For these we need Young s modulus, GPa Steel Aluminum Copper Zinc Lead PEEK PP PTFE Material bar-charts Material property charts WC CFRP Alumina GFRP Glass Fibreboard Young s modulus (GPa) Young's Modulus (GPa) e-003 e-004 Low alloy steel High carbon steel Stainless steel Cu-alloys Zn-alloys Al-alloys Mg-alloys Ti-alloys Acetal, POM Polyester, rigid PS ABS PUR PC PE PP PTFE Ionomer EVA Polyurethane Natural Rubber (NR) M aterials:\met ALS M aterials:\polymers Materials:\CERAMICS and GLASSES M aterials:\composites Untitled WC BC SiC Glass Ceramic Silica glass Alum ina Soda-Lime glass Al-SiC Composite KFRP CFRP GFRP Plywood Neoprene Metals Polymers Ceramics Ceramics & glass Composites Hybrids Metals Polymers Ceramics Hybrids ME Fall 2006 CES - Explore relationships Elementary selection ( Find materials with large modulus ) ME Fall 2006 CES -2 3

4 Material property- charts: modulus - density Mechanical properties 000 Why the differences? Young s modulus E, (GPa) Woods Foams Composites Ceramics Polymers Metals Atom size and weight Bonds as (linear) springs Spring constant for various bond types. Manipulating properties Making composites Making foams 0.0 Elastomers 0. 0 Density (Mg/m 3 ) 00 ME Fall 2006 CES -3 ME Fall 2006 CES -4 Thermal properties Providing methods and tools Why the differences? Bonds as non-linear springs 0% expansion at melting point, so expansion goes inversely as Tm Thermal energy as atom vibration, propagates as waves, scattered by obstacles Manipulating properties High conductivity: purity Low conductivity, obstacles and foams At this stage students have a tool. Materials that are light and stiff? Materials with low expansion? with high conductivity? Develops a perspective ME Fall 2006 CES -5 ME Fall 2006 CES -6 4

5 Creating charts Report writing Toolbar Browse Select Search Print Search web Select what? Materials, Level New Graph stage Limit stage Tree stage Property 2 Property File Open project Save project Print. Edit Copy Paste. Acrylonitrile-butadiene-styrene (ABS) - (CH2-CH-C6H4) n General Properties Electrical Properties Density Mg/m^3 Conductor or insulator? insulator Price US $/kg Optical Properties Transparent or opaque? Opaque Mechanical Properties Young's Modulus GPa Eco Properties Elastic Limit 8-50 MPa Energy content 9-0 MJ/kg Tensile Strength MPa CO Elongation 6-8 % 2 per kg kg/kg Hardness - Vickers 6-5 HV Endurance Limit - 22 MPa Corrosion and Wear Resistance Fracture Toughness MPa.m /2 Flammability Fresh Water Organic Solvents Thermal Properties Sea Water Max Service Temp K UV Thermal Expansion /K Wear Poor Specific Heat J/kg.K Thermal Conductivity W/m.K What is it? ABS (Acrylonitrile-butadiene-styrene ) is tough, resilient, and easily molded. It is usually opaque, although some grades can now be transparent, and it can be given vivid colors. ABS-PVC alloys are tougher than standard ABS and, in self-extinguishing grades, are used for the casings of power tools. Design guidelines. ABS has the highest impact resistance of all polymers. It takes color well. Integral metallics are possible (as in GE Plastics' Magix.) ABS is UV resistant for outdoor application if stabilizers are added. It is hygroscopic (may need to be oven dried before thermoforming) and can be damaged by petroleum-based machining oils. ABS can be extruded, compression moulded or formed to sheet that is then vacuum thermo-formed. It can be joined by ultrasonic or hot-plate welding, or bonded with polyester, epoxy, isocyanate or nitrile-phenolic adhesives. Technical notes. ABS is a terpolymer - one made by copolymerising 3 monomers: acrylonitrile, butadiene and syrene. The acrylonitrile gives thermal and chemical resistance, rubber-like butadiene gives ductility and strength, the styrene gives a glossy surface, ease of machining and a lower cost. In ASA, the butadiene component (which gives poor UV resistance) is replaced by an acrylic ester. Without the addition of butyl, ABS becomes, SAN - a similar material with lower impact resistance or toughness. It is the stiffest of the thermoplastics and has excellent resistance to acids, alkalis, salts and many solvents. Typical Uses. Safety helmets; camper tops; automotive instrument panels and other interior components; pipe fittings; home-security devices and housings for small appliances; communications equipment; business machines; plumbing hardware; automobile grilles; wheel covers; mirror housings; refrigerator liners; luggage shells; tote trays; mower shrouds; boat hulls; large components for recreational vehicles; weather seals; glass beading; refrigerator breaker strips; conduit; pipe for drain-waste-vent (DWV) systems. The environment. The acrylonitrile monomer is nasty stuff, almost as poisonous as cyanide. Once polymerized with styrene it becomes harmless. ABS is FDA compliant, can be recycled, and can be incinerated to recover the energy it contains. Property ME Fall 2006 CES -7 ME Fall 2006 CES -8 The main points Classification allows materials data to be organized and retrieved The data take two broad forms: (a) numeric, non-numeric data that can be structured in a uniform way for all materials (b) supporting, best stored as text and images Visual presentation of data as bar-charts and property (bubble) charts reveals relationships and allows comparisons The CES EduPack allows rapid access to, and ability to make charts ME Fall 2006 CES -9 5