The test was intended for use with applicants and incumbents for jobs where knowledge and skill in the area of CNC operation is a necessary part of job activities. Job analysis activities conducted during development of this test revealed that an applicable title is Nesting Operator as defined in the Dictionary of Occupational Titles (U.S. Department of Labor, 1991).
007.362-010 NESTING OPERATOR, NUMERICAL CONTROL (aircraft mfg.) alternate titles: computer-numerical-control nesting operator; pattern data operator.
Operates computer to lay out graphic display of parts to be machined in optimum arrangement (nest) and generate control media for numerical-control drilling, routing, and cutting machines: Reviews shop orders to determine job specifications and nesting requirements. Sorts shop orders into groups according to compatibility factors, such as quantity and shape of parts, and type, size, alloy, and gauge of material to be machined to produce nest that maximizes material utilization and minimizes machine setup and operation. Enters computer commands to retrieve stored parts data and graphic displays such as simulated patterns or templates, and displays and manipulates part images on computer screen into optimum arrangement. Calculates and codes machine controlling criteria, such as table movement, type and size of cutting and drilling tools, spindle location, and machining start point, feed rate, and speed, utilizing knowledge of numerical-control machine operation. Enters commands to title and store nest layouts in computer memory and to build and maintain source files. Keys in commands to transfer nest data, listings, or layouts to other media, such as hard copy, tape, or floppy disk, or to route nest data by direct link to direct-numerical-control machines. Loads and unloads disk packs, tapes, or floppy disks. May operate digitizing equipment to produce patterns. May discuss nesting or machining problems with machine operators or other personnel.
Norman Bleier, author of a popular text on CNC, was asked to list significant areas of job knowledge for CNC Operators. He then wrote a series of multiple-choice questions in each area. This resulted in a series of 60 questions in 7 areas as shown in Table 1 below.
CNC OPERATOR TEST
FORM CNC-2RBC (2009)
A. General Knowledge – 8
B. Coordinate Systems – 15
C. Interpolation – 9
D. Tape Code and Program Structure – 8
E. Tool Compensation – 5
F. M-Codes – 3
G. Operations – 12
Total # of Questions – 60
Please contact us for pricing and more information. Sample questions are not available for this instrument. Sample copies are available for purchase only.
We recommend that test validation be conducted for an organization that meets any of the following criteria:
- Is a highly visible national or international company
- Has more than 200 employees
- Has a labor agreement
- Has a federal contract
- Has ever had an EEO charge
- Needs professional assistance for setting cutting scores on tests
The Uniform Guidelines on Employee Selection Procedures (1978)1, developed by the EEOC, Civil Service Commission, Department of Labor and Department of Justice, are intended to establish a uniform Federal position in the area of prohibiting discrimination in employment practices. Regarding the use of tests and other selection procedures, the Guidelines state:
These guidelines apply to tests and other selection procedures which are used as a basis for any employment decision. Employment decisions include but are not limited to hiring, promotion, demotion, membership (for example, in a labor organization), referral, retention, and licensing and certification, to the extent that licensing and certification may be covered by Federal equal employment opportunity law. Other selection decisions, such as selection for training or transfer, may also be considered employment decisions if they lead to any of the decisions listed above. (Section 2B)
The Guidelines also state:
The use of any selection procedure which has an adverse impact on the hiring, promotion, or other employment or membership opportunities of members of any race, sex, or ethnic group will be considered to be discriminatory and inconsistent with these guidelines, unless the procedure has been validated in accordance with these guidelines. (Section 3A)
From the employer’s perspective, it is very useful to have a job-related test. When tests are job related, they have more credibility with the persons taking them, giving the test takers more confidence in their results and providing less likelihood of complaint or litigation. A validated test is usually the product of research by a psychologist. The resulting validation report is the documented evidence by a professional researcher of the validity of the selection procedure. In the event of complaint or litigation, the report would usually be entered into evidence. In addition, the author would provide testimony that the report reflects generally-accepted professional practice and is in conformance with the requirements of the Uniform Guidelines on Employee Selection Procedures.
1 Equal Employment Opportunity Commission, Civil Service Commission, Department of Labor, and Department of Justice. (1978, August). Uniform guidelines on employee selection procedures. Federal Register, 43, 38290-38315.
© Ramsay Corporation