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99 Cards in this Set
- Front
- Back
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In what two ways can shearing machine types be broken down into |
Shear design and the drive systems |
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What are the two common design types for power squaring shears |
The guillotine also known as a slider unit and the swing beam |
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What are the two systems run by the motor on a shear |
Hydraulic system and a mechanical system |
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What is the range of metal thickness the power shears are capable of cutting |
30 gauge and an excess of 1/4 inch plate steel |
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What is the cutting length on the most common power shears today |
8 foot cutting length up to a 16-foot cutting length |
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How much does stainless reduce the shears capacity |
By 4 gauges |
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What is a variable rake |
Rake angle that can adjusted to suit the length of the part that is being cut |
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One should not expect a good cut on a strip that is smaller than what? |
8 times the material thickness |
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What is the swing beam style sheer |
Uses one of the drive system to Pivot the moving blade down on roller bearings which eliminates the need for guides as it keeps the blades in proper position as they pass |
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What is a hydraulic shear |
It's a 2-cylinder guillotine style plate Shear with variable rake angle and variable blade clearance |
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What is a direct-drive mechanical shear |
Operator steps on a pedal to turn on the motor bring the bean down and to make the cut motor turns off at the end of the cycle and the blade Beam returns to the top of the stroke |
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What is the direct drive mechanical Shear design suitable for |
Shear's that are not in constant use because the machine uses power only when it is activated |
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What are most mechanical machines being purchased today used for |
10 gauge thickness and lengths up to 12 ft |
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For safety reasons what must be known about the mechanical shear |
That the Mobile blade cannot be stopped once it is activated it will make a complete cycle |
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List all the 9 parts of a shear |
Bed, side gauge, that gauge, knives, hold down fingers, knife guard, foot treadle, control panel and Shadow line |
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What is the bed |
Flat horizontal portion in front of the sheer |
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What is the side gauge |
Portion of the sheer that is used to keep the material at 90° to this shear knives also has a ruler built-in for measuring material |
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What is the back gauge |
Backguage on the Shears are adjustable allows you to make multiple cut simultaneously and accurately it speeds up production |
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What is the important maintenance that must be done to this shear's knives |
They must stay Sharp and proper clearances, clearance has become too large the metal being cut will be left with a burr |
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What are the hold down fingers |
Located in the front of the knives they're usually hydraulically run and come down before the knives to hold the metal in place |
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What are the knife guards |
Mounted directly in front of the whole down fingers to keep you from accidentally slipping your fingers into them knives and or hold down fingers |
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What is the foot treadle |
Foot pedal that activates this shear when it is depressed |
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What is the control panel |
Located at the front of this shear and the Point at which you can set up the length and the materials gauge and where the back gauge is adjusted |
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What is the shadow line |
Provides a guide for cutting material at a specific location when using the back or side gauge is not practical |
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What is rake angle |
Shearing angle made between the upper and lower Shear knife of a guillotine style shear or ironworker flat bar shear |
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Why is The Rake angle of the blade important |
Because it determines the quality of the cut, the lower the rake angle the better the quality of the cut |
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Blade clearance |
The distance between the upper and lower Shear knives |
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Why is blade clearance important |
Because it prevents Burrs which are caused by placing the blades too far apart for the given material thickness |
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What are the 12 safety rules for 4 using the power shear |
1 protective equipment must be worn at all times 2 never operate a power brake without being trained 3 the shear and the area around it need to be kept Clean and Free of scrap metal 4 the operator will use the proper material support mechanical assist or a helper when handling heavy materials 5 I realize our fingers are other body parts to enter the point of operation or pinch points 6 do not operate this year if it's not functioning properly 7 never modifier tamper with a sheer or its wiring 8 always keep safety in mind and be mentally alert 9 do not operate equipment when impaired by alcohol or drugs 10 never operate this year when someone is behind it 11 never remove any of the safety guards 12 never try to reach around the back of the sheer when you're cutting |
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What are two ways a power brake press are driven |
They can be mechanical or hydraulic |
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On a mechanical brake press what is important to remember once the foot treadle is pressed |
But the brake press run a full cycle there's no stopping it as it comes down to make the bend |
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How is the brake press capacity rated |
In tons |
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What is the stroke length |
Amount of travel of the moving beam and is adjustable with the punch and die in place |
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What is the opening height |
The distance between the lower surface of the top beam and the upper surface of the bottom beam when the movable beam is at its maximum stroke length with no dies in place |
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What is the overall length the brake press |
The distance from the left side to the right side of the brake tool |
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What is the throat depth |
Distance of the cutouts in the side frame machine housing that determines the maximum length of flange that can be turned when bending to overall length of machine |
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What is the distance between housings |
Distance between the side frames of the break allowing for free passage of material between frames |
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Why are mechanical stops used on the brake press |
To ensure repeatability in the stopping of the Ram at the same position |
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What is a feature of the mechanical stops |
It has a high low speed that allows you to change the speed of the moving die automatically reduce speed as it comes closer to the material to reduce whip up |
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What is coining or bottom bending |
Method of bending where material is expected to take shape from the forming punch requires more pressure but is more accurate |
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What is airbending |
Is the method where the material is expected to take the shape from the amount of depth penetration of the punch is more versatile but less accurate |
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What is a bend allowance |
The amount of compensation considered for the stretch of the material at the bending point in order to produce the proper flange dimension |
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What is inside radius |
The radius on the inside of a bent part |
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What is Bend angle |
The angle that is obtained between the two successive flanges |
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What is the flange length |
measured from the centre of the dye opening to the backstop |
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What is back gauge position |
The front of the back gauge fingers or gauging bar to the centre of the V opening being used in the die |
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What is the punch and the die |
The upper tool is known as the punch the bottom tool is known as the die |
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What is a knife punch |
Normally has a 30 degree angle Edge and is very useful when sharp bends are required also known as an acute angle punch |
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What is a gooseneck punch |
It has an offset built into it to accommodate bends that are close to each other, very useful when performing channels or deep boxes |
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What is the lower die |
Lower tool the punch uses to form Bend angles and must match the punch being used for safe operation |
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What is the V die opening |
The dimension of the opening of The Bottom die |
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What is a hemming die |
Special combination allowing for the production of bends by performing a sharp Bend then flattening it on a second operation |
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What is a flattening die |
Used to complete a hem or to bend materials to a given degree of a previously formed acute angle, can also be used to straighten out material that has been formed incorrectly |
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What are rubber or urethane rubber dies |
Another forming method used to press a shape into a rubber block or die |
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What is the use of the rubber die |
Keeps the material against the upper die or punch to duplicate the shape of the upper die |
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What are the advantages of rubber dies |
1 you can form unlimited shapes 2 you will not cause as much scuffing or marking on your work 3 your setup time is reduced because the lower die change is eliminated |
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What are the disadvantages of rubber dies |
1 you will need more power to press into the rubber die it requires double the tonnage compared to standard male female press break dies 2 rubber dies will deteriorate much faster 3 replacing rubber dies has a high replacement cost |
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What can be used on conventional V dyes to eliminate scuffing or marks |
Rotator or roll form guides should be used |
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What is the advantage and disadvantage of Rotator dies |
The advantage is the elimination of scuffing and marking the disadvantage is the cost of the die |
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What are the three basic methods of bending used in forming sheet metal |
Coining, bottom bending and airbending |
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What is coining |
The material being formed actually spreads or flows, it is the most accurate but requires the highest amount of pressure |
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And coining it is not uncommon to exceed what pressures |
50 tons per inch when coining |
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What is bottom bending |
Used in medium-to-high production, similar to coining, excellent for producing sharp Corners with consistent accuracy |
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What is the clearance between the punch and die if over bend requirements are small for a Sharp radius |
Slightly less than the metal thickness |
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What can happen if the clearance between the punch and die is decreased too much |
Pressure increases rapidly and can cause fracture in the dye the sheet or damage to the brake press |
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How can this be avoided |
It would be better to put an over bend in the angle on the punch and die |
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What can be done to decrease deflection causing irregularity in the Bend |
Shimming under the dye has deflection is greatest in the centre |
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What does airbending offer |
Less accuracy but requires less tonnage |
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How is the required angle produced with airbending |
Adjusting the depth through which the punch enters the die opening allowing the operator to over break the metal sufficiently to compensate for spring back |
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What results in a smaller die opening |
A smaller radius a larger die opening results in a larger radius and more spring back |
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What is the approximate inside radius formed in relation to the die opening |
Is approximately one-sixth of the die opening |
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What is the usual practice to die opening |
8 times the material thickness for material half an inch and less and 10 times the material thickness for 1/2 inch and over, which increases the radius and reduces the possibility of a fracture at the bend |
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What happens in the area of the bend |
The outer surface is stretched in the inner surface is compressed |
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What is the surest most accurate method to determine bend allowance |
Make a trial Bend of the metal being used |
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What are the advantages of airbending |
The vast types of forming that can be performed with the Limited amount of die and punches, minimal pressure required preventing strain on the brake press |
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What are the disadvantages of air bending |
The inconsistency of the bends due to the variations in metal thickness and structure |
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How can springback be compensated |
By over bending a material slightly |
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What does a generic tonnage chart show |
Approximate pressure in tons per linear foot required to make a 90-degree Bend using air bending dies |
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What are the 12 power brake safety rules |
1 protective equipment must be worn 2 do not use without training 3 the break-in area needs to be kept clean and free of scrap 4 use proper material supports mechanical assist her helper when handling heavy materials V don't allow your fingers or body parts into the point of operation or pinch points 6 do not operate the brake if it is not functioning properly 7 do not tamper or modify 8 keep safety in mind and be mentally alert 9 do not operate when your alcohol or drugs 10 refrain from wearing loose-fitting clothing or jewellery 11 do not change die when brake is running always disconnect the power 12 do not operate the brake when someone is at the rear of the break |
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What is considered heavy gauge material |
10 to 16 gauge |
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What happens to heavy gauge material when it is rolled or bent |
The outside surface stretches the inside surface shrinks |
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What is the mean diameter |
Mean diameter is a place where the shrinking stops and the stretching starts |
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What is the difference between rolled and and bent heavy gauge material |
Rolled material shrink and stretch evenly, bent material shrinks and stretches unevenly |
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What happens When rolling heavy-gauge material into a cylindrical shape |
There is usually as much shrinking as there is stretching, the mean diameter is in the exact centre of the material |
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How do you calculate the mean diameter of a cylinder |
Add one material thickness to the inside diameter |
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How do you calculate the cut length of a cylinder |
The mean diameter times pi |
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What type of materials stretch more than they shrink |
Harder materials such as common grade stainless steel |
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How do you calculate the mean radius of harder metals |
Inside radius plus 30% of the metal thickness |
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What type of materials shrink more than they stretch |
Softer materials such as aluminum and Lead |
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On softer materials how much can be lost to shrinkage in a 90 degree Bend |
As much as 20% of the dimension |
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How do you calculate the mean radius for softer metals |
Inside radius + 50 to 60% of material thickness |
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When laying out with items containing 90 degree bends what is the setback |
Setback is the same Dimension as the metal thickness |
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How do you calculate the stretch out of a 90-degree Bend radius |
Calculate the mean diameter and then divide by 4 to get the stretch out of the radius Bend |
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What do you need to remember when determining your forming needs |
Smaller die produces a sharper Bend radius requiring more tonnage, a wider die gives a larger radius requiring less tonnage increasing the amount of spring back can be overcome by over bending |
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For materials up to 1/2 inch would the inside radius be when air bending |
Equal to the thickness of the material |
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When constructing elbows what must be used for stretch outs and profile |
Mean diameter |
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On elbows thickness will affect the fit up at mitre joints it doesn't affect the mitre angle but will change the mean radius how do you adjust for this |
You must grind back two edges to the mean diameter |
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What is the angle that must be ground for a bevel joint |
30 degrees on each Edge produce a 60 degree V |
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If the frustum height is critical on a cone what must be done |
A partial elevation view must be drawn to determine the correct mean diameters and radius points for both the large and small ends |
