Shop And Welding Flashcards
Power press brakes can either be?
Mechanical or hydraulic
All power press brakes are rated in?
Tons
If you are using a 120 ton brake that measures 10’ in length, how many tons of braking power do you have per foot?
12 tons per foot
120 / 10 = 12
What is the amount of travel of the moving beam and is adjustable on press brakes?
Stroke length
What is the distance between the lower surface of the top beam and the upper surface of the bottom beam when the moveable beam is at its maximum stroke length with no dies in place?
Opening height
What is the distance from the left side to the right side of the brake tooling?
Overall length
What is used in certain types of hydraulic press brakes to ensure the stopping of the ram at the same position?
Mechanical stops
Name three types of bending on a power press brake?
Coining -stamping
Bottom bending
Air bending
When the material is expected to take its shape from the amount of depth penetration of the punch, this is known as?
Air bending
Which form of bending requires the least amount of pressure?
Air bending
What must you do to the thickness of the metal when using inside dimensions?
Add 20%
To calculate outside dimensions, what do you need to do to the thickness of the metal you are working with?
Subtract 80%
What is the name of the upper bending tool on a power brake?
The lower bending tool?
Upper is punch
Bottom is die
What die can be used to straighten out material that has been formed incorrectly?
Flattening die
What are 2 disadvantages of working with rubber dies?
They deteriorate much faster
They have a high replacement cost
What type of die can be used if a quality finish is desired?
Roll form or rotator dies
Which is the most accurate method of bending?
Coining
Which method of bending produces sharp corners with consistent accuracy?
Bottom bending
How many times the material thickness should the die opening be when air bending material up to and including 1/2” thick?
8 times the material thickness
How many times the material thickness should the die opening be if you are air bending material over 1/2” thick?
10 times the material thickness
What can be done to ensure the most accurate method to determine bend allowance?
Test piece
What is the biggest disadvantage of air bending?
Inconsistency of the bends due to the variation of metal thickness and structure as it comes from the mill
Is it ok to bend material using numbers above the bolded numbers on a tonnage chart?
It is dangerous and will cause unsafe pressures
Is it acceptable to remove the guards on a power shear?
No
Two design types of power squaring shears are?
Guillotine (slider)
Swing beam
Power shears are electrically run with the motor being of what two type of systems?
Hydraulic or mechanical
Power shears can cut from what gauge to material in excess of what?
From 30 gauge to in excess of 1/4” plate steel
When using a shear, stainless steel reduces the shear’s capacity by how many gauges?
4 gauges
Guillotine type shears require a what to keep the blade beams in the proper position?
Guiding system
What can be adjusted on a guillotine type machine to suit the length of the part that is being cut?
The rake angle
Good cuts cannot be expected on a strip that is smaller than how many times the material thickness?
8 times
How are the blades kept in proper position on a swing beam style shear?
A drive system pivots the moving blade down on roller bearings
What type of shear only uses power when it is activated?
Direct drive mechanical shear
Mechanical shears are faster and have a better design for cutting certain types of material. To what gauge and length can they cut?
To 10 gauge and 12’
What is the flat horizontal portion in front of the shear?
The bed
What is used on the side of the shear that keeps the material at 90 degrees to the shear knives?
Side gauge
What part on the shear is adjustable allowing you to make multiple cuts simultaneously and accurately?
Back gauge
If the shear knives are not kept sharp, what can be left on the material being cut?
Burrs
The piece that is mounted directly in front of the hold down fingers used to keep you from slipping your hands into the knife area is called what?
Knife guards
A pedal attached by a cable or running the entire length of the shear is the?
Foot treadle
What component sets up the length and materials gauge as well as adjusts the back gauge?
Control panel
What is the angle made between the upper and lower shear knives?
Rake angle
It is better to have a lower rake angle? True or false
True, the cut will be of better quality
Distance between the upper and lower shear knives is the?
Blade clearance
When can the guards on a power shear be removed?
Never, they are there for your safety!
How much residual pressure at pounds per square inch should remain in a cylinder to avoid atmospheric contamination of its interior?
25 psi
Name the three basic types of metal transfer methods in GMAW welding?
Short circuit transfer
Globular transfer
Spray arc transfer
When working with current and voltage in welding, what sets the arc length and what sets the speed?
Voltage sets the arc length and wire speed sets the heat
If voltage is too low and wire speed is too high what is this referred to as?
Stubbing
What type of welding does not require a shielding gas?
FCAW Flux cored arc welding
What is the purpose of the shielding gas?
To prevent the weld metal from absorbing elements from atmospheric air
What is the thermal conductivity of a gas?
It is the gases ability to conduct heat
Which gas has the higher thermal conductivity, argon or helium?
Helium
What type of gas is used to weld aluminum?
Argon which is approximately 1.4 times heavier than air
What is the typical flow rate for argon-oxygen shielding gas when welding steel?
25 CFH (cubic feet per hour)
What causes porosity in the weld metal?
Moisture
