Question 1
During wire EDM, each pulse is followed by a period of off-time. What is the primary purpose of that off-time?
Show answer & explanation
Correct answer: D - It allows the dielectric to de-ionize and debris to flush from the gap
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The EDM II exam has 82 questions and runs 1 hour 30 minutes.
These 10 free EDM II questions are organized by exam domain, so you can see how each part of the EDM II (2-Axis Wire) blueprint is tested. Reveal the answer and explanation under each question.
During wire EDM, each pulse is followed by a period of off-time. What is the primary purpose of that off-time?
Correct answer: D - It allows the dielectric to de-ionize and debris to flush from the gap
A wire EDM is set up with 0.010 inch diameter wire and is cutting with approximately 0.002 inch of overburn per side. What is the resulting kerf width?
Correct answer: C - 0.0140 inch
A 2-axis wire EDM cut produces a wall that measures 0.0009 inch wider at the bottom of the part than at the top. What is the MOST likely cause?
Correct answer: B - The wire is not perpendicular to the machine table
A 3 inch thick hardened blank is being roughed. The wire cuts stably through the section but breaks repeatedly at the point where it exits the far side of the workpiece. What is the MOST likely cause?
Correct answer: C - Flushing support is lost as the wire breaks out through the far surface
Compared with plain brass wire of the same diameter, a zinc-coated wire generally cuts faster because:
Correct answer: D - Zinc vaporizes at a low temperature, absorbing energy and aiding flushing
An operator increases pulse on-time to speed up a roughing cut. Which combination of effects should be expected?
Correct answer: A - Faster cutting, rougher surface finish, and larger overburn
A roughing pass and three skim passes are run on the same die profile. Between passes, what changes?
Correct answer: C - The offset value and power settings; the programmed geometry does not change
The dielectric conductivity on a wire EDM has climbed well above the recommended range for the material being cut. What cutting symptom is MOST likely?
Correct answer: D - Discharges initiate prematurely and erratically, destabilizing the cut
A wire EDM program calls G41 before cutting an external punch profile. G41 places the wire:
Correct answer: A - To the left of the programmed path, viewed along the direction of travel
A feature control frame specifies profile of a surface, 0.0005, referenced to Datum A. Unless the drawing indicates otherwise, the tolerance zone is:
Correct answer: A - 0.0005 inch total, equally disposed about the true profile
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