Student Workbook for Programming of CNC Machines. Ken Evans

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СКАЧАТЬ a reference tool; just like your machinist tools, it was designed to help you get the job done. Whenever it is possible, consult with your trainer for additional ideas or methods to evaluate your work.

      STUDENT WORKBOOK

      to accompany

      PROGRAMMING OF

      CNC MACHINES

      Fourth Edition

      Unit 1: CNC Basics

      Process Planning

      Any time a new part is considered for manufacture, it is necessary to have a logical plan in order to machine it efficiently. The following is an explanation of the exercise requirement: Three Process Planning Sheets are provided on the following pages for operations (Chart 1-1), setup (Chart 1-2), and quality control (Chart 1-3). Copy as many as you need. Later in the workbook, CNC Programming Sheets are included for the units covering Turning Center Programming and Machining Center Programming. For a detailed description of the use of these documents, please refer to Programming of CNC Machines, Fourth Edition, Part 1, CNC Basics. You will also find in the units covering Turning Centers and Machining Centers a list of cutting tools that can be used for preparing the Process Planning Sheets.

      Use the Operation Sheet (Chart 1-1) to identify each individual operation and the machines necessary to complete the part in the blueprints that follow.

      Use the CNC Setup Sheet (Chart 1-2) to identify work holding, cutting tools, work piece coordinate zero locations, and any other pertinent information needed to complete the part setup for these blueprints. Refer to the tool lists provided in Unit 3 (CNC Turning Center Programming) and Unit 4 (CNC Machining Center Programming) to choose the appropriate tools.

      Use the Quality Control Check Sheet (Chart 1-3) to list 100% of the dimensional data needed to verify that the parts are made to specification, starting with the blueprints in Figures 1-1 and 1-2.

Figure 1-1 Turning Center Process Planning

Chart 1-1 Process Planning Operation Sheet

Date	Prepared By
Part Name	Part Number
Quantity	Sheet ___ of ___
Material
Raw Stock Size
Operation Number	Machine Used	Description of Operation	Time

      In the example in Figure 1-1, the parts are provided as 3.0625 long slugs with one end having already been faced. It will be necessary to clamp the 2.50 diameter in pre-machined soft jaws with enough material extended to allow machining of the part, including removal of 1/16 inch from the face of the part. The material is 4340 alloy steel. Dimensional tolerances are as follows: .X = plus or minus .015 inch, .XX = plus or minus .010 inch, .XXX = plus or minus .005 inch, and angular tolerance is plus or minus .5 degree. Please use copies of the Process Planning sheets and develop a plan to machine the part to dimensional requirements.

Chart 1-2 Process Planning CNC Setup Sheet

Date	Prepared By
Part Name	Part Number
Machine	Program Number

      Workpiece Zero: X___________ Y __________ Z _________

      Setup Description:

ToolNumber

OffsetNumber

Tool Description

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