1.16 Metal Processes Flashcards
(64 cards)
1
Q
Describe the term forming
A
No material is removed, but materials are deformed to produce required shapes
2
Q
Describe the term redistribution
A
The material is changed from one form to another, e.g. liquid metal poured into a mould to take a solid shape
3
Q
Describe the term wastage
A
Material is cut away to leave the desired shape
4
Q
What are the metal forming processes?
A
- press forming
- spinning
- cupping
- deep drawing
- forging
- drop forging
- bending
- rolling
casting:
* sand casting
* die casting
* investment casting
* low temperature casting (pewter)
5
Q
State two features of press froming
A
Process form: Forming
- Shapes sheet metal into 3D forms
- Often used in conjunction with robots for lifting the sheet into place
- Suitable for mass production or large-scale batch production
6
Q
What are the detailed steps involved in the press forming process?
A
- Material Preparation: A flat sheet of metal, often called a ‘blank’, is cut to size. This blank must be clean, flat, and free from burrs to avoid imperfections in the final product.
- Positioning in the Die: The metal blank is placed on the die (female tool), and often held in place using a blank holder or clamping ring. This prevents the metal from slipping or wrinkling during the forming process.
- Pressing: A punch (male tool) moves downward and applies force to the sheet, pushing it into the die cavity. The shape of the die determines the final form of the product. The metal undergoes plastic deformation, which means it permanently changes shape without springing back.
- Forming and Stretching: The material is stretched and sometimes compressed to fill the die shape. This must be carefully controlled to avoid tearing, thinning, or wrinkling of the material.
- Releasing: Once the desired shape is formed, the punch retracts, and the formed component is removed from the die.
- Finishing Operations: Often, excess material (called flash) is trimmed, and sharp edges are deburred. In some cases, secondary operations like piercing holes, embossing, or folding flanges may follow.
7
Q
State two features of wrought iron forging
A
Process type: Forming
- Uses wrought iron (carbon content less than 0.8%)
- Can be hand or hydraulic press process
- Suitable for one-off or small-batch production
8
Q
What is the general step-by-step process of forging?
A
- Heating the metal (optional): Most forging is done hot (between 950–1250°C for steel), to make the metal malleable without melting it.
- Placing the billet: A billet (a roughly cut piece of metal) is positioned on an anvil or die surface.
- Applying compressive force: A hammer or press is used to deform the metal into the required shape. The metal’s grain structure flows along with the deformation, increasing strength.
- Repositioning and reheating: For complex shapes, the part may be reheated and forged multiple times.
- Finishing: The forged part may be trimmed, machined, or heat-treated to achieve the final dimensions and properties.
9
Q
State two features of cupping and deep drawing
A
Process form: Forming
- Starts with a metal blank
- Metal is stretched into shape
- Used for large-scale mass or continuous production
10
Q
What is the detailed step-by-step process of cupping?
A
- Blank preparation: A flat circular metal blank is cut from a sheet. The blank must be free from defects and have uniform thickness to ensure even forming.
- Die and punch set-up: The blank is placed over a female die cavity. A male punch, slightly smaller than the die cavity, is aligned with the blank.
- Clamping with a blank holder: A blank holder or pressure ring clamps the metal in place to control the material flow and prevent wrinkling during deformation.
- Punching (cupping) begins: The punch presses the blank into the die, stretching the metal around the punch and down into the cavity. The sides of the cup form as the metal flows inward and downward.
- Material flow control: Throughout the forming, controlled pressure and lubrication are used to allow the metal to stretch without tearing. Wrinkling, thinning, or tearing may occur if the pressure is too high or too low.
- Part removal: Once the cup shape is formed, the punch retracts, and the finished cup is removed. If further depth is needed, the component may go through secondary drawing operations.
11
Q
What are the detailed step-by-step stages of the deep drawing process?
A
- Blank preparation: A flat, round metal blank is cut to the correct size, ensuring uniform thickness and a clean surface.
- Die and punch set-up: The blank is placed over a die cavity. A punch (with a slightly smaller diameter than the die) is aligned to press into the die.
- Clamping: A blank holder or pressure ring is applied to stop the material from wrinkling or slipping during forming. This must be carefully tensioned.
- Initial draw: The punch moves downwards, pressing the blank into the die cavity. The material stretches and flows into the cavity, forming a shallow cup.
- Redrawing (if needed): For very deep parts, the piece may go through multiple redraw stages, where it’s re-clamped and drawn deeper using larger presses or differently shaped punches.
- Finishing operations: The final product is removed from the die. Trimming is often done to remove excess material or flanges. Additional processes such as
- flanging, piercing, or ironing (to even out wall thickness) may follow.
Proper lubrication is essential throughout to reduce friction and prevent tearing or surface damage.
12
Q
State two features of drop forging
A
Process type: Forming
- Use for products that need to be tough and hard
- Maintains the internal grain structure which retains the strength
- Hot metal billet shaped on an anvil or die and then pressed into shape and cooled
- Suitable for mass production
13
Q
What are the detailed steps in the drop forging process?
A
- Billet heating: The metal is heated to its plastic state to make it malleable but not molten.
- Positioning in the die: The hot billet is placed in the bottom die, which has half the shape of the final part.
- Drop of the hammer/ram: The top die, attached to a hammer or ram, is dropped repeatedly onto the billet, forcing the metal into the shape of the closed die cavity.
- Flash formation and trimming: Excess material (called flash) squeezes out of the die and is trimmed off after forming.
- Cooling and finishing: The forged part is cooled, then may undergo finishing operations like grinding, machining, or heat treatment.
14
Q
State two features of spinning
A
Process form: Forming
- Product may show parallel lines where the sheet has been forced onto the mandrel
- Suitable for mass production or small-batch production
15
Q
What is the detailed step-by-step process of metal spinning?
A
- Blank preparation: A circular sheet of metal (blank) is cut to size and deburred. The blank must be flat, smooth, and of even thickness.
- Mounting the mandrel: A mandrel or former is fixed to the headstock of a lathe. The mandrel’s shape is an exact match of the internal profile of the final product.
- Positioning the blank: The blank is clamped tightly between the mandrel and a pressure plate or tailstock to hold it in place during spinning.
- Rotation begins: The lathe spins the mandrel and blank at high speed, generating centrifugal force and softening the metal slightly due to frictional heat.
- Forming: A roller tool (manual or automated) is pressed against the spinning blank. The operator gradually moves the tool along the surface of the mandrel, shaping the metal to conform to it.
- Finishing: After the desired shape is achieved, the part is released from the mandrel. Trimming may be done to remove excess metal, and polishing or heat treatment can be carried out if needed.
In automated spinning, computer control allows for repeated precision and can include processes like shear spinning (which also reduces wall thickness).
16
Q
How suitable is bending for different scales of production?
A
Bending is highly versatile and can be used for:
One-off or low-volume production, using manual tools like vices or press brakes
Medium- to high-volume production, with automated CNC bending machines
Because tooling is relatively inexpensive and setups are quick, bending is cost-effective across a wide range of scales. It’s especially well-suited to industries like:
Construction (e.g. metal framing)
Furniture (e.g. metal legs or enclosures)
Consumer products (e.g. sheet-metal casings)
However, for extremely high volumes of identical, complex parts, stamping or press forming may be more efficient.
17
Q
What is the detailed step-by-step process of bending sheet metal?
A
- Material selection and preparation: The metal sheet is cut to size and cleaned. The thickness and type of metal determine the bend radius and tooling.
- Marking and positioning: The bend lines are marked precisely. The sheet is aligned on the bending tool — typically a press brake or folding machine.
- Clamping: The sheet is held securely between a punch and die (in a press brake), or with clamps (in a folding machine).
- Bending action: The punch is driven down onto the metal, pressing it into the die and creating a bend. In a folding machine, the clamped sheet is folded upwards or downwards along a straight edge.
- Springback compensation: Once released, the metal may spring back slightly due to its elasticity. This is accounted for in the tooling or programming.
- Final check and finishing: The bent part is inspected for angle accuracy, surface finish, and consistency. Sharp edges may be deburred.
18
Q
How suitable is rolling for different production scales?
A
Rolling is used almost exclusively in mass production, particularly in heavy industry. It is ideal for:
Continuous production of sheet, bar, or plate metal
Structural components in construction, automotive, or shipbuilding
Pre-processing material for stamping, cutting, or drawing
The machinery and energy costs are high, so it’s not suitable for low-volume or custom one-off parts. However, the cost per unit drops significantly with scale, making it highly economical for large output.
19
Q
What is the step-by-step process of hot rolling?
A
Hot Rolling:
- Preheating the metal: The metal is heated to above its recrystallisation temperature (e.g. ~1200°C for steel) to improve plasticity and reduce the force needed.
- Initial rough rolling: The ingot is passed through roughing rolls to reduce its size and begin shaping.
- Final rolling passes: It’s passed through finishing rolls that gradually reduce the thickness and define the final dimensions.
- Cooling: The metal is cooled in a controlled way to prevent warping or internal stresses.
- Coiling or cutting: The product is either coiled (if strip/plate) or cut to size.
20
Q
Describe the term addition/fabrication
A
Process where components and products are made by adding pieces together
21
Q
State two features of sand casting
A
Process type: Redistribution
- Labour-intensive process
- Not a high-quality surface finish
- Suitable for one-off or small-batch production
22
Q
What is the step-by-step process of sand casting?
A
- Pattern creation:
A replica of the final object (the pattern) is made from wood, plastic, or metal.
It includes allowances for shrinkage and draft angles to ease removal from the sand.
- Mould preparation:
The pattern is placed in a moulding box (flask) and packed tightly with special casting sand.
The box is made in two halves: the cope (top) and drag (bottom).
The pattern is carefully removed, leaving a cavity in the shape of the part.
- Core setting (if required):
If the part has internal cavities, a sand core is inserted into the mould to create hollow sections.
- Mould assembly:
The cope and drag are reassembled.
Channels are added to allow molten metal in (sprue) and air/gas to escape (risers/vents).
- Pouring:
Molten metal is poured carefully into the mould via the sprue.
- Cooling and solidification:
The metal is allowed to cool and solidify fully. This can take minutes to hours depending on the size.
- Breaking the mould:
Once solid, the sand is broken away to release the casting.
- Finishing:
The part is cleaned, and any excess material (like sprues or risers) is cut off.
The casting may be machined or ground to achieve tight tolerances or surface finishes.
23
Q
State two features of rolling
A
Process type: Forming
- Hot rolling metal results in uniform mechanical properties, no deformation or stress
- Surface is usually coated with carbon deposits, which must be removed using acid pickling
- Cold rolling results in a material that has a tighter tolerance and better surface finish
24
Q
State two features of gravity die casting
A
Process type: Redistribution
- Lower melt point metals such as aluminium, aluminium alloys and zinc-based alloys
- Relies on gravity to help the metal flow into the mould
- Used for thicker mould sections
- Used for very large-batch and mass production
25
What is the step-by-step process of die casting?
1. Mould preparation:
A steel die is created with two halves (the core and the cavity), which are often cooled with water channels to speed up solidification. The die is coated with a lubricant to aid ejection of the cast part.
2. Melting the metal:
The metal (usually in ingot form) is melted in a furnace until it reaches the required temperature for casting.
3. Injection:
The molten metal is injected into the die at high pressure (up to several thousand psi) through an injection nozzle. This pressure ensures that the metal fills every part of the die, including intricate details.
4. Cooling and solidification:
The molten metal cools and solidifies in the die. This process is rapid due to the high thermal conductivity of the die, which draws heat from the metal.
5. Ejection:
Once solidified, the die is opened, and the casting is ejected using mechanical pins or air pressure. The die is closed again for the next cycle.
6. Post-processing:
Excess material such as flash (a thin layer of metal around the part) is removed, often through trimming, and the part may undergo additional processes like machining or surface finishing for final accuracy.
26
State two features of pressure die casting (hot chamber)
Process type: Redistribution
- Lower melt point metals such as aluminium, aluminium alloys and zinc-based alloys
- Molten metal stored in a shot of molten metal is forced into the die
- Fast process
- Used for very large-batch and mass production
27
State two features of pressure die casting (cold chamber)
Process type: Redistribution
- Lower melt point metals such as aluminium, aluminium alloys and zinc-based alloys
- Molten metal ladled into shot chamber and hydraulically pushed into the chamber
- Used for very large-batch and mass production
28
State two features of investment casting (lost wax casting)
Process type: Redistribution
- Used for intricate or awkward shapes that would be difficult or impossible to mould using any other casting process
- High quality, excellent finish
- Wax patterns are cast from a master mould repeatable quality process
29
What is the step-by-step process of investment casting?
1. Pattern creation:
A wax pattern of the part is created, typically by injection moulding the wax. This pattern replicates the exact shape of the final product.
2. Assembly of the pattern:
The wax pattern is attached to a sprue (a central channel) and a runner system (to distribute the metal) to form a tree. Multiple patterns can be attached to a single tree for efficient casting.
3. Shell formation:
The wax assembly is repeatedly dipped in a ceramic slurry and then sprinkled with fine sand. This creates a thick shell around the wax, which hardens as the slurry dries. This is repeated several times to build a strong, durable shell.
4. Wax removal (de-waxing):
The shell is heated in an oven to melt and remove the wax, leaving behind a hollow ceramic shell. The wax is collected and reused in many cases.
5. Metal pouring:
The ceramic shell is heated to a high temperature to prepare it for molten metal. The molten metal is then poured into the shell, filling the cavity where the wax was previously.
6. Cooling and solidification:
The molten metal is allowed to cool and solidify inside the ceramic shell. Cooling rates are controlled to prevent defects.
7. Shell removal:
Once the metal has cooled, the ceramic shell is broken away, often using a hammer or vibration. The casting is now revealed.
8. Finishing:
Any leftover metal (flash) is removed, and the casting is cleaned, polished, and sometimes machined to achieve the desired dimensions and surface finish.
30
State two features of low temperature pewter casting
Process type: Redistribution
- Used for school or college workshops
- Can be used with a simple MDF mould
- Suitable for one-off production or small batch (with aluminium moulds)
31
What is the step-by-step process of low-temperature casting (pewter)?
1. Mould preparation:
The first step is to prepare a mould (often made of sand, plaster, or silicone for non-industrial uses). The mould can be one-part (if the object is simple) or two-part (for more complex shapes).
The mould must be cleaned and treated with a release agent to ensure the pewter does not stick to the surface.
2. Melting the pewter:
The pewter alloy is placed in a crucible and heated using a furnace or a torch until it reaches its melting point (around 230°C). The molten pewter is kept at a consistent temperature for easy pouring.
3. Pouring the molten pewter:
Once the pewter is fully melted, it is carefully poured into the prepared mould. The pouring process must be done gently to avoid air bubbles or defects in the casting.
4. Cooling and solidification:
The molten pewter is left to cool and solidify. Due to the low melting point of pewter, solidification typically takes just a few minutes, depending on the size and complexity of the part.
5. Mould removal:
Once the pewter has cooled and solidified, the mould is broken or removed to reveal the casting. For sand or plaster moulds, this may involve carefully breaking apart the mould, while silicone moulds can simply be peeled away.
6. Finishing:
The cast part may have excess material, such as flash (extra metal around the edge). This is removed using trimming tools.
The part may then be polished, sanded, or brushed to achieve the desired finish. Some castings may be patinated (a surface treatment) to give the pewter a worn or antique appearance.
Additional details such as engraving or stone setting may be added at this stage for decorative items.
32
State two features of MIG welding
Process type: Addition
- Uses an electrode wire
- Suitable for thin-gauge metals, medium carbon steel or aluminium
- Uses an inert gas such as CO2 or argon
- Suitable for one-off fabrication or on an assembly line e.g. car chassis
33
What is the step-by-step process for MIG welding?
1. Setup: Choose the appropriate wire feed and shielding gas (commonly argon or a mixture of CO2 and argon) based on the materials.
2. Trigger pull: Press the trigger on the welding gun to begin the continuous wire feed through the gun.
3. Arc formation: The electrode wire touches the base material, creating an electric arc that generates heat.
4. Melting: The heat from the arc melts both the wire electrode and the base material.
5. Filling the gap: The melted filler metal and the molten base metal flow together to form a weld pool.
6. Cooling: The molten pool cools to form a solid, fused joint.
7. Finish: Release the trigger and inspect the weld for consistency.
34
State two features of TIG welding
Process type: Addition
- Uses a filler rod
- Accurate, strong welds but requires high skill levels and is quite a slow method
- Uses an inert gas (argon/helium)
35
What is the step-by-step process for TIG welding?
1. Preparation: Select the tungsten electrode (non-consumable) and set up the shielding gas (typically argon).
2. Arc initiation: Activate the machine to create an electric arc between the tungsten electrode and the workpiece.
3. Heat generation: The arc generates heat, melting the base material. The tungsten electrode does not melt.
4. Filler material (optional): If needed, add a filler rod by feeding it into the molten weld pool.
5. Welding: Maintain a steady hand to move the torch across the joint, controlling the heat and filling the joint as necessary.
6. Cooling: Once the welding is complete, allow the joint to cool and solidify.
7. Inspection: Inspect the weld for any defects, such as cracks or insufficient penetration.
36
State two features of oxy-acetylene welding
Process type: Addition
- Uses a steel filler rod
- Useful for quick repair jobs or in remote locations where there is no electric power supply
37
What is the step-by-step process for oxy-acetylene welding?
Set up equipment: Connect oxygen and acetylene tanks to the welding torch.
Adjust gas flow: Set the appropriate flow rates of oxygen and acetylene to create the desired flame temperature.
Ignite the flame: Light the acetylene first, then gradually adjust the oxygen flow to produce a neutral flame.
Heat the base metal: Direct the flame at the joint between the two base metals, heating them until they reach a molten state.
Add filler material: If necessary, add a filler rod to the molten pool to strengthen the joint.
Weld the joint: Move the flame steadily along the joint, ensuring complete fusion of the metals.
Cool and inspect: Let the weld cool, and inspect for strength and appearance.
38
State the feature of spot welding
Process type: Addition
- Sheet held between two copper electrodes that form a weld when the charged electrodes make contact with the metal
39
What is the step-by-step process for spot welding?
1. Clamping: Position the metal sheets between the two copper electrodes.
2. Electrode pressure: Apply sufficient pressure to hold the sheets together firmly.
3. Current flow: Pass electric current through the electrodes to create a localized heat at the contact point between the sheets.
4. Heat generation: The heat from the electrical resistance melts the metal at the contact point, forming a molten pool.
5. Weld formation: The molten metal solidifies, creating a small weld nugget that bonds the sheets together.
6. Cooling: Remove the pressure and allow the joint to cool.
40
State the feature of soldering
Process type: Addition
- Uses a filler material of a lower melting point than the metal being joined. Typically, solders are an alloy of tin and copper
41
What is the step-by-step process for soldering?
1. Preparation: Clean the surfaces of the workpieces to remove any dirt, oxidation, or grease.
2. Heat the workpieces: Use a soldering iron to heat the joint to just below the melting point of the solder.
3. Melt the solder: Feed the solder wire into the joint. The solder should melt and flow into the gap between the two workpieces.
4. Cooling: Remove the soldering iron and let the solder cool and solidify to create the bond.
5. Inspection: Check the bond for strength and ensure no gaps remain.
42
State two features of brazing (hard soldering)
Process type: Addition
- Uses a brass filler rod
- Carried out using either oxy-acetylene or a gas and compressed air brazing hearth suitable for one-off production or small batch (with aluminium moulds)
- Used to join dissimilar metals such as mild steel sheet to aluminium copper and nickel
43
What is the step-by-step process for brazing?
1. Surface cleaning: Clean the surfaces of the workpieces to remove contaminants.
2. Apply flux: Apply a flux to prevent oxidation during heating.
3. Heat the base metal: Use a torch to heat the workpieces to just below their melting point.
4. Melt the filler metal: Heat the filler metal (usually a brass or silver alloy) to its melting point.
5. Capillary action: The molten filler metal flows into the joint via capillary action between the base materials.
6. Cooling: Allow the joint to cool and solidify.
7. Inspection: Inspect the joint to ensure that it is securely bonded.
44
State the feature of riveting
Process type: Addition
Riveting uses two pieces that are overlapped and drilled. The end of the shaft is then hammered over to join
45
What is the step-by-step process for riveting?
Prepare the workpieces: Drill a hole in both pieces of metal where the rivet will be inserted.
Insert the rivet: Insert the rivet through the holes in the two workpieces.
Expand the rivet: Use a rivet gun or manual tool to expand one end of the rivet, forming a permanent bond.
Secure the rivet: The expanded end of the rivet holds the metal pieces tightly together.
Inspection: Ensure that the rivet has properly formed and is secure.
46
State the feature of soldering
Process type: Addition
Uses a filler material of a lower melting point than the metal being joined. Typically, solders are an alloy of tin and copper
47
State the feature of pop riveting
Process type: Addition
Pop riveting uses a rivet gun (or riveting pliers) and a rivet and pin. Good for where the underside of the joint is inaccessible
48
State the feature of milling
Process type: Wastage
The milling machine can run in the x-direction (left and right horizontally), y-direction (forward and backward horizontally), and z-direction (up and down vertically) to cut slots, shape edges, or thread holes.
49
What is the detailed step-by-step process of milling?
1. Secure the workpiece firmly to the milling table using clamps or a vice.
2. Choose and fit the cutting tool (e.g. end mill, slot drill) based on the cut type and material.
3. Set the spindle speed, feed rate, and depth of cut appropriate to the material.
4. Zero the machine using datum edges or the surface of the material.
5. Begin the cut by lowering the cutting tool into the workpiece to the desired depth.
6. Move the cutting tool along the programmed or manual path (X, Y, and sometimes Z axes).
7. Repeat passes if required for deeper cuts, adjusting depth gradually.
8. After finishing, retract the tool and stop the spindle.
9. Deburr the edges and clean the machined part for inspection.
50
State the feature of turning
Process type: Wastage
The workpiece is held with a three or four jaw chuck in the headstock whilst the cutting tool moves in two axes.
51
What is the detailed step-by-step process of turning?
1. Clamp the cylindrical workpiece securely in the lathe chuck.
2. Select the appropriate cutting tool (e.g. facing, parting, profiling) and install it on the tool post.
3. Set the lathe’s spindle speed depending on the material and desired surface finish.
4. Position the tool close to the workpiece but not touching it.
5. Start the machine and begin facing to create a flat reference surface.
6. Perform parallel turning by feeding the tool along the length to reduce the diameter.
7. Make multiple shallow passes for dimensional accuracy.
8. Add chamfers, tapers, or grooves as required.
9. Use a parting tool to separate the component if needed.
10. Clean and check for finish and tolerance.
52
State the feature of flame cutting
Process type: Wastage
- Uses oxy-acetylene gas and a special flame-cutting torch to deliver a very intense and focused flame above 3,500°C.
- Difficult to maintain a parallel line with high levels of tolerance
53
What is the detailed step-by-step process of flame cutting?
1. Clamp the metal sheet onto a safe, non-combustible cutting surface.
2. Connect and adjust oxygen and fuel gas regulators (e.g. acetylene).
3. Open the gas valves on the torch and ignite the flame using a flint striker.
4. Adjust the flame to a neutral or slightly oxidising flame (bright inner cone).
5. Preheat the metal with the flame tip until it reaches ignition temperature (~900°C).
6. Engage the oxygen jet to create an oxidation reaction with the heated metal.
7. The metal melts and is blown away as slag along the cut line.
8. Guide the torch steadily along the desired path.
9. Once complete, turn off the oxygen and fuel, and allow cooling.
10. Remove slag and inspect the cut.
54
State the feature of plasma cutting
Process type: Wastage
- Plasma is a super-heated ionised gas that is electrically conductive.
- Plasma cutting generates a faster, cleaner cut than flame cutting
55
What is the detailed step-by-step process of plasma cutting?
1. Connect the plasma cutter to power and compressed air (or nitrogen).
2. Attach the earth clamp securely to the workpiece or cutting bed.
3. Position the torch tip close to the material without touching it.
4. Start the machine and pull the trigger to create a pilot arc.
5. The plasma arc initiates and melts the metal instantly along the cut line.
6. A high-velocity stream of ionised gas blows molten metal away.
7. Move the torch steadily to follow the path — CNC or manual.
8. Release the trigger to stop the arc once the cut is complete.
9. Let the metal cool, and clean up slag or burrs.
56
State the feature of laser cutting
Process type: Wastage
- More accurate and uses less energy than plasma cutting but cannot cut the same thickness of the material
- Lower-powered lasers are used in schools and colleges to cut acrylic sheets and manufacture boards such as MDF and plywood.
57
What is the step-by-step process of laser cutting?
1. Design creation: A vector-based design is produced in CAD software.
2. File preparation: The file is saved in formats like DXF or SVG and imported into the laser cutter software.
3. Material setup: A clean, flat sheet of paper or board is placed on the laser bed, held flat with pins or weights.
4. Settings adjustment: The laser’s power and speed are adjusted to avoid scorching or overburning.
5. Fume extraction check: Extraction systems are turned on to remove smoke and burnt particles.
6. Cutting or engraving: The laser follows the programmed design path, cutting or scoring the material.
7. Finishing: Once cooled, parts are removed and checked for accuracy; any burn marks may be cleaned.
58
State the feature of punching/stamping
Process type: Wastage
- Uses computer-controlled machines that stamp out sections of sheet material
- Suitable for small and medium-size production runs and it is normally used for processing metals from 0.5mm to 6mm thickness.
59
Punching process
Punching is when a tool (punch) forces through a sheet of metal to make a hole by shearing it against a die (a shaped opening).
How It Works:
A flat metal sheet is placed over a die.
A punch (a hard metal tool) pushes down with great force.
The metal is sheared and the unwanted piece (called the slug) is pushed out.
This leaves a clean hole or cut-out shape in the metal.
60
stamping process
Stamping includes punching but can also mean shaping the metal without cutting it, using pressure to form designs, logos, or 3D patterns.
Types of Stamping:
Blanking – cutting out a shape from the sheet
Embossing – raising or lowering parts of the surface
Coining – pressing fine details into the metal (like coins)
Bending – forming angles in the sheet
61
State the three types of temporary fasteners and joining methods
- Self-tapping screws
- Machine screws
- Nut and bolt
62
What are self-tapping screws?
Self-tapping screws are screws that are designed to create their own hole as they are driven into the material, eliminating the need for pre-drilling. They are commonly used for joining metal, plastic, or wood.
63
What are machine screws?
Machine screws are screws with uniform threads that are typically used with nuts or tapped holes in machines and mechanical components. They are commonly made of steel or stainless steel and used in applications where precise, strong fastening is required.
64
What are nuts and bolts?
Nuts and bolts are fasteners used to join two or more parts together. The bolt is inserted through a hole in the parts, and the nut is threaded onto the bolt to secure it. The combination of the bolt and nut provides a strong, detachable joint.
