Podcast
Questions and Answers
What is one advantage of epoxide resins over other plastic materials?
What is one advantage of epoxide resins over other plastic materials?
- They are less expensive than Zinc alloys.
- They have better compression properties. (correct)
- They can be easily molded into any shape.
- They are heavier than cast iron.
In which situation is it not economical to use plastic tools?
In which situation is it not economical to use plastic tools?
- When producing small quantities. (correct)
- For conventional tool shapes. (correct)
- For components made of plastic materials.
- When components are heavy.
What is a disadvantage of using plastic tools compared to metal tools?
What is a disadvantage of using plastic tools compared to metal tools?
- Plastic tools can be reinforced effectively.
- Plastic tools are more fragile. (correct)
- Both are equally effective in all applications.
- Plastic tools are heavier than steel tools.
What is a common application of plastic tools in various industries?
What is a common application of plastic tools in various industries?
What feature do most unit heads include to enhance drilling capabilities?
What feature do most unit heads include to enhance drilling capabilities?
What characteristic of thermo-setting plastics prevents them from being welded using conventional processes?
What characteristic of thermo-setting plastics prevents them from being welded using conventional processes?
Which welding process uses hot gas to join plastic parts?
Which welding process uses hot gas to join plastic parts?
How does heat transfer occur in welding processes that utilize an external heat source?
How does heat transfer occur in welding processes that utilize an external heat source?
What is a key benefit of welding compared to cementing and riveting in plastic applications?
What is a key benefit of welding compared to cementing and riveting in plastic applications?
What types of processes generate heat within the workpiece for welding plastics?
What types of processes generate heat within the workpiece for welding plastics?
What happens to plastic workpieces during the welding process?
What happens to plastic workpieces during the welding process?
What is a common filler material used in hot-gas welding?
What is a common filler material used in hot-gas welding?
What is a significant drawback of hot gas welding?
What is a significant drawback of hot gas welding?
How is the joint completed in hot gas welding?
How is the joint completed in hot gas welding?
The hot tool welding process primarily relies on what method to join materials?
The hot tool welding process primarily relies on what method to join materials?
Which type of joint is commonly made using hot gas welding?
Which type of joint is commonly made using hot gas welding?
What happens to the edges of materials before they are hot gas welded?
What happens to the edges of materials before they are hot gas welded?
What are the cold rollers used for in the hot gas welding process?
What are the cold rollers used for in the hot gas welding process?
In hot tool welding, what occurs after the hot blade has softened the surfaces?
In hot tool welding, what occurs after the hot blade has softened the surfaces?
What is a negative consequence of low joint strength in a welding process?
What is a negative consequence of low joint strength in a welding process?
Which of the following is NOT a characteristic of hot tool welding?
Which of the following is NOT a characteristic of hot tool welding?
What is one of the main benefits of using the hot machining process?
What is one of the main benefits of using the hot machining process?
Which of the following is NOT a method of special processing discussed?
Which of the following is NOT a method of special processing discussed?
What characteristic of heat-resistant materials poses a challenge during machining?
What characteristic of heat-resistant materials poses a challenge during machining?
Which specification is relevant for Plastic Extruders?
Which specification is relevant for Plastic Extruders?
In what scenario are conventional machining methods most challenging?
In what scenario are conventional machining methods most challenging?
What is a consequence of machining heat-resistant materials?
What is a consequence of machining heat-resistant materials?
Which of the following benefits is associated with foam moulding?
Which of the following benefits is associated with foam moulding?
What is a disadvantage of the plastic casting process?
What is a disadvantage of the plastic casting process?
How does work-hardening affect the machining of heat-resistant materials?
How does work-hardening affect the machining of heat-resistant materials?
What parameter must be considered in the selection of cutting tools for hot machining?
What parameter must be considered in the selection of cutting tools for hot machining?
What is essential for achieving extremely close dimensional accuracy in mould design?
What is essential for achieving extremely close dimensional accuracy in mould design?
What is the main function of the plunger in a plastic mould?
What is the main function of the plunger in a plastic mould?
Which of the following statements about mould design is false?
Which of the following statements about mould design is false?
In an injection mould, what does the single parting line indicate?
In an injection mould, what does the single parting line indicate?
What role do temperature control channels play in a mould?
What role do temperature control channels play in a mould?
What is NOT part of the basic components of a mould?
What is NOT part of the basic components of a mould?
What does the term 'knockout pin' refer to in mould design?
What does the term 'knockout pin' refer to in mould design?
Which of the following is critical to avoid problems in shape generation during mould design?
Which of the following is critical to avoid problems in shape generation during mould design?
What does the support plate in a mould primarily function as?
What does the support plate in a mould primarily function as?
Which component primarily assists in the removal of the fabricated parts from moulds?
Which component primarily assists in the removal of the fabricated parts from moulds?
Which method is primarily used for producing large mass plastic tools such as forming dies and punches?
Which method is primarily used for producing large mass plastic tools such as forming dies and punches?
What is a key advantage of using plastic tools for short runs and prototypes?
What is a key advantage of using plastic tools for short runs and prototypes?
Which alloy is NOT commonly formed using plastic tools?
Which alloy is NOT commonly formed using plastic tools?
What process is used to create precision thin-section metal parts by depositing metal onto a form?
What process is used to create precision thin-section metal parts by depositing metal onto a form?
What addition is typically made to casting resin to enhance its properties?
What addition is typically made to casting resin to enhance its properties?
In hot tool welding, what is the purpose of the heating wedge?
In hot tool welding, what is the purpose of the heating wedge?
What is the role of the roller in the hot tool welding process?
What is the role of the roller in the hot tool welding process?
How is heat transferred in the hot press welding method?
How is heat transferred in the hot press welding method?
What specific characteristic makes hot tool welding suitable for elastic materials?
What specific characteristic makes hot tool welding suitable for elastic materials?
What does the term 'scarfed edges' refer to in the context of hot press welding?
What does the term 'scarfed edges' refer to in the context of hot press welding?
In the hot plate welding process, what is the main function of the resistance element?
In the hot plate welding process, what is the main function of the resistance element?
What is the purpose of allowing the workpieces to stay under pressure after reaching welding temperature in hot press welding?
What is the purpose of allowing the workpieces to stay under pressure after reaching welding temperature in hot press welding?
Which of the following welding processes requires one of the pieces to be a body of revolution with a circular section at the joint?
Which of the following welding processes requires one of the pieces to be a body of revolution with a circular section at the joint?
What primary action occurs in ultrasonic welding that distinguishes it from other welding methods?
What primary action occurs in ultrasonic welding that distinguishes it from other welding methods?
Which welding method includes the use of a viscous filler material that aids in forming a strong bond?
Which welding method includes the use of a viscous filler material that aids in forming a strong bond?
In high-frequency induction welding, what is primarily applied to complete the joint after heating the plastics?
In high-frequency induction welding, what is primarily applied to complete the joint after heating the plastics?
What is a significant limitation of friction welding in plastics?
What is a significant limitation of friction welding in plastics?
Which welding technique allows crossover of dissimilar plastics during the joint formation?
Which welding technique allows crossover of dissimilar plastics during the joint formation?
What is primarily responsible for generating heat in nuclear welding?
What is primarily responsible for generating heat in nuclear welding?
Which of these materials cannot typically be joined using high-frequency induction welding?
Which of these materials cannot typically be joined using high-frequency induction welding?
What is a potential outcome of using the extruded-filler welding process?
What is a potential outcome of using the extruded-filler welding process?
Which of the following materials is NOT commonly used for moulds?
Which of the following materials is NOT commonly used for moulds?
What is a typical characteristic of the steel used for moulds as described?
What is a typical characteristic of the steel used for moulds as described?
What is the primary advantage of using flash type cavity design?
What is the primary advantage of using flash type cavity design?
Which type of component is usually made from plate steel?
Which type of component is usually made from plate steel?
What is the recommended hardness for drill rods used in mould pin production?
What is the recommended hardness for drill rods used in mould pin production?
Which component is typically obtained by carburization in mould design?
Which component is typically obtained by carburization in mould design?
Which of the following is considered a disadvantage of flash type cavity design?
Which of the following is considered a disadvantage of flash type cavity design?
What is the primary material that cavity designs utilize for creating mould frames?
What is the primary material that cavity designs utilize for creating mould frames?
What is the main disadvantage of using hardening on frame components?
What is the main disadvantage of using hardening on frame components?
Which property of materials generally makes them suitable for mould production?
Which property of materials generally makes them suitable for mould production?
What is the minimum recommended wall-thickness for mouldings?
What is the minimum recommended wall-thickness for mouldings?
What is an appropriate rib height in relation to its thickness?
What is an appropriate rib height in relation to its thickness?
Why is it better to avoid sharp corners in mould design?
Why is it better to avoid sharp corners in mould design?
What is a recommended maximum variation in wall thickness of a moulding?
What is a recommended maximum variation in wall thickness of a moulding?
What factor primarily determines the curing time of a plastic product?
What factor primarily determines the curing time of a plastic product?
What should the length-to-diameter ratio for through holes typically not exceed?
What should the length-to-diameter ratio for through holes typically not exceed?
What geometric feature is recommended to enhance the strength of a moulded part?
What geometric feature is recommended to enhance the strength of a moulded part?
What is the disadvantage of using thick corners in mould design?
What is the disadvantage of using thick corners in mould design?
What is one of the functions of providing adequate fillets in mould design?
What is one of the functions of providing adequate fillets in mould design?
What is the recommended depth-to-diameter ratio for blind holes larger than 1.5 mm?
What is the recommended depth-to-diameter ratio for blind holes larger than 1.5 mm?
Flashcards
Plastic Welding
Plastic Welding
A process that joins plastic pieces by applying heat and pressure, resulting in the plastic material becoming a viscous liquid and fusing together.
Hot-Gas Welding
Hot-Gas Welding
The specific welding process where a stream of hot gas melts the edges of the plastic pieces, and a filler rod is used to create a solid joint.
External Heat Welding
External Heat Welding
A category of welding processes that use external sources of heat, like a flame, to melt the plastic surfaces.
Internal Heat Welding
Internal Heat Welding
Signup and view all the flashcards
Thermoplastic Properties
Thermoplastic Properties
Signup and view all the flashcards
Thermosetting Plastics
Thermosetting Plastics
Signup and view all the flashcards
Autohesion
Autohesion
Signup and view all the flashcards
Hot Gas Welding with Rollers
Hot Gas Welding with Rollers
Signup and view all the flashcards
Hot Tool Welding
Hot Tool Welding
Signup and view all the flashcards
Hot Blade Welding
Hot Blade Welding
Signup and view all the flashcards
Direct Heat Welding
Direct Heat Welding
Signup and view all the flashcards
Lap Joint
Lap Joint
Signup and view all the flashcards
Butt Joint
Butt Joint
Signup and view all the flashcards
Scarfing
Scarfing
Signup and view all the flashcards
Joint Strength
Joint Strength
Signup and view all the flashcards
Plastic Tooling
Plastic Tooling
Signup and view all the flashcards
Epoxide Resin
Epoxide Resin
Signup and view all the flashcards
Intricate Shapes in Plastic Tooling
Intricate Shapes in Plastic Tooling
Signup and view all the flashcards
Limitations of Plastic Tools
Limitations of Plastic Tools
Signup and view all the flashcards
Applications of Plastic Tools
Applications of Plastic Tools
Signup and view all the flashcards
Grinling or Machining Allowance
Grinling or Machining Allowance
Signup and view all the flashcards
Mould Design for Plastic Parts
Mould Design for Plastic Parts
Signup and view all the flashcards
Cavity
Cavity
Signup and view all the flashcards
Plunger
Plunger
Signup and view all the flashcards
Frame Components
Frame Components
Signup and view all the flashcards
Operating Members
Operating Members
Signup and view all the flashcards
Compression Mold
Compression Mold
Signup and view all the flashcards
Injection Mold
Injection Mold
Signup and view all the flashcards
Parting Line
Parting Line
Signup and view all the flashcards
Temperature Control Channels
Temperature Control Channels
Signup and view all the flashcards
Hot Machining
Hot Machining
Signup and view all the flashcards
Heat-Resisting Materials
Heat-Resisting Materials
Signup and view all the flashcards
Work-Hardening
Work-Hardening
Signup and view all the flashcards
Shear Strength
Shear Strength
Signup and view all the flashcards
Machining
Machining
Signup and view all the flashcards
Thermal Conductivity
Thermal Conductivity
Signup and view all the flashcards
Cutting Tool Materials
Cutting Tool Materials
Signup and view all the flashcards
Tool Geometry
Tool Geometry
Signup and view all the flashcards
Tool Life
Tool Life
Signup and view all the flashcards
Tensile Strength
Tensile Strength
Signup and view all the flashcards
Hot Wedge Welding
Hot Wedge Welding
Signup and view all the flashcards
Hot Press Welding
Hot Press Welding
Signup and view all the flashcards
Electro-forming
Electro-forming
Signup and view all the flashcards
Electrolyte
Electrolyte
Signup and view all the flashcards
Anode
Anode
Signup and view all the flashcards
Forming Tool
Forming Tool
Signup and view all the flashcards
Building Up Reinforced Layers
Building Up Reinforced Layers
Signup and view all the flashcards
Friction Welding
Friction Welding
Signup and view all the flashcards
Ultrasonic Welding
Ultrasonic Welding
Signup and view all the flashcards
High Frequency Induction Welding
High Frequency Induction Welding
Signup and view all the flashcards
Extruded-Filler Welding
Extruded-Filler Welding
Signup and view all the flashcards
Nuclear Welding
Nuclear Welding
Signup and view all the flashcards
Minimum Wall Thickness
Minimum Wall Thickness
Signup and view all the flashcards
Flat Surfaces in Plastic Design
Flat Surfaces in Plastic Design
Signup and view all the flashcards
Mold materials
Mold materials
Signup and view all the flashcards
Flash Type mold design
Flash Type mold design
Signup and view all the flashcards
Cavity design
Cavity design
Signup and view all the flashcards
Alloy steels for molds
Alloy steels for molds
Signup and view all the flashcards
Flash Type cavity design
Flash Type cavity design
Signup and view all the flashcards
Study Notes
Processing of Plastics
- Plastics deform at elevated temperatures, behaving like highly viscous liquids. Welding requires pressure.
- Thermosetting plastics cannot be welded conventionally.
- Thermoplastics can repeatedly transition to highly elastic and plastic states without losing properties.
- Welding is superior to cementing and riveting for permanent connections in terms of speed, labor cost and joint quality.
- Welding processes are classified based on heat source.
- External heat sources like hot gas, hot filler metal, and hot tools. Heat is transferred by convection, conduction and radiation.
- Generated heat inside the workpiece from sources like RF current, ultrasound, friction, etc.
Hot-Gas Welding
- Hot gas heats the edges and filler rods to a viscous state.
- Similar to manual gas welding of metals.
- Drawbacks include low joint strength, limited plasticity, slow welding speed, especially in thick sheets, and operator skill dependence.
- Can be used to weld films, creating lap joints without filler rods, enhancing efficiency.
Hot Tool Welding
- Hot tool transfers heat to the workpiece via direct contact.
- Several variations exist. Some involve placing a hot blade between parts, while others use a hot wedge that's moved along the weld line.
- Suitable for thicker parts as well as for lap and butt joints over a surface area.
- Applicable for plastics that are unsuitable for rf induction heating (e.g., PTFE, polyethylene, polystyrene)
Friction Welding
- Converts mechanical energy to heat at the welded surfaces.
- Similar to metal friction welding.
- Limitations: One of the parts must be a rotational body, and at the joint the cross section must be a circle or annulus; a flash forms during pressure application.
Ultrasonic Welding
- Uses ultrasonic energy to weld plastics.
- Similar process as metal ultrasonic welding.
- Suitable for acrylics, PVCs, and polystyrene.
- No edge preparation or filler needed.
- Applicable to dissimilar plastics
High Frequency Induction Welding
- Uses an electric field between electrodes.
- Similar to the method for metals.
- Filler rod is in viscous fluid state
Extruded-Filler Welding
- The filler rod is in a viscous fluidic state and it melts the edges of the plastic.
- Suitable for films and heavy gauge sheets
Nuclear Welding
- Uses neutron irradiation to generate heat for fusion joining.
- Not suitable for materials that become radioactive upon irradiation.
Infrared Welding
- Uses infrared to transfer heat for welding.
- Suitable for joining polyethylene films.
Joining Thermosets
- Thermosets do not soften upon heating.
- Joining involves adhesive methods or mechanical fasteners.
- Solvent bonding involves surface roughening, solvent wiping, and surface pressing until bond strength is achieved.
Design of Plastic Parts
- Mould design minimizes problems, considering shape and dimensional control.
- Uniform wall thickness is important for curing time.
- Avoiding undercuts and providing adequate fillets minimizes stress concentration.
- Proper rib and/or dome configurations increase the rigidity of parts.
- Simple part shapes facilitate removal from molds.
- Holes should have sufficient wall thickness to prevent cracking.
- Tolerances are necessary for manufacturing variations in tools, materials, or machining.
- The amount of tolerance is based on part dimensions and intended use.
Warpage Allowance
- Warpage is a measure of the deformation of a part.
- This is an undesirable effect, especially in thin parts.
- A good measure to use for warpage is + or - 0.075mm per mm.
Mould Material
- Steel alloys are commonly used in mold manufacturing.
- Other materials like Aluminum, Berrylium Copper, and Zinc may be used, based on application.
Mould Design
- There are different types of cavity designs for molds.
- These designs are called Flash type, Positive type, Semi-positive type, and Landed Plunger type, and Sub-cavity type.
- These designs differ in the way in which parts are loaded into the mold.
- Each design entails varying degrees of complexity and the selection depends on the complexity of the component.
Surface Cleaning and Treatments
- Cleaning is needed for part assembly, to prevent component failure due to accumulated debris, and to allow a better quality for decorative application.
- Cleaning methods include mechanical methods such as barrel tumbling and abrasive blasting, chemical methods such as alkaline and solvent cleaning, and vapor degreasing.
- Mechanical cleaning removes scale, dirt and debris.
- Chemical cleaning removes oils and greases and is suitable for parts of aluminum, lead, and zinc.
- Electrolytic and ultrasonic methods are used for intricate shapes.
Coating and Plating
- Metallic coatings like copper, chrome, cadmium and nickel are applied electrochemically.
- Hot-dip coatings (e.g., tin, zinc, lead, and aluminum alloys) involve immersing the part in molten metal.
- Conversion coatings like phosphate or chromate form a protective layer on the part surface
Hot Machining
- Localized heat allows for easy chip formation, reducing workpiece strength and enabling easier machining.
- It is primarily applied to heat resistant metals for better machining performance, reduced wear, better surface finish, and less shock to cutting tools.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Test your knowledge on the various processes involved in the processing of plastics. This quiz covers topics such as welding methods, thermoplastics, and thermosetting plastics, providing insight into their behavior at different temperatures. Additionally, explore the advantages of welding over other methods for permanent connections.
