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''development and implementation of concepts, procedures
and designs to achieve and maintain required levels of
compatibility, interchangeability or commonality.''
Cost - do
(it's only industrial
engineering fundamentals and simple algebra).
for analyzing machining performance.
hours = base time + allowances
hours = standard hours / efficiency
= standard hours / actual hours
hours = actual hours + delays
= standard hours / paid hours
hours = standard hours / yield
= actual hours / paid hours
Machining Parameter -
(feed, speed, depth-of-cut, horsepower,
material & geometry).
Fundamental working knowledge in
principles. Emphasis on material removal processes performed on
computerized numerically controlled (CNC) lathes and machining centers.
Detailed information illustrated for selecting the following
conditions: feed, speed, depth-of-cut, horsepower, cutting tool
and geometry. Comprehensive machining data reference material.
2 Volume, 2,304 page Machining Data Handbook containing
related to cutting conditions based on a wide variety of workpiece
machining operations and tooling materials. These texts are the
standard of the industry. This 2 volume set is from the Institute of
Advanced Manufacturing Sciences, Inc. IAMS is a not-for-profit national
information analysis center for applied research, development and
Their mission is to enhance the competitiveness of companies by
the implementation of technology and improving business practices,
upon the resources of industry, academia and government.
software is the
Data Handbook for a multi-task Windows environment, containing the most
comprehensive listing of feeds, speeds, power requirements and metal
rates in the world.
Material Groups: Carbon Steels; Free Machining Stainless Steels;
Material Composition & Hardness: Machining Operations; Turning
Single Point and Box Tools; Face Milling; End Milling -
Drilling; Reaming; Boring; Counterboring & Spotfacing; Tapping.Tool
Materials: General Guidelines for Selection of Materials; High Speed
Steels; Carbides; Coated Carbides.
Geometry: Single Point Turn, Bore, Form & Cutoff; Single Point
Thread & Tap Thread; End Mill & Face Mill; Drill, Oil-Hole
Spade Drill; Reamer.
Fluids: Function of Cutting Fluids; Type of Cutting Fluids;
Selection of Cutting Fluids.
for Turning, Milling & Drilling: Cutting Speed, SFM; Revolutions
Per Minute, RPM; Feed Rate, IPM; Feed Rate Per Tooth, IPT; Cutting
Minutes; Rate of Metal Removal, Cubic Inches Per Minute; Horsepower;
Guidelines: General Machining Guidelines; Guidelines for Drilling;
Tool Life; Types of Machinability Data.
formulas to derive the machining parameters
based on the work piece material type and condition.
(simply make the observations in your environment,
you'll be surprised).
direct and indirect labor tasks performed in cnc machining
A simple definition of setup time
the total base tasks plus allowance factors for the time it takes to go
from the last piece in the present work order to the first good piece
the next work order.
Setup time can range from 5% to 95%
of the time applied to a work order. The percentage increases as
the lot size decreases, significantly effects the unit cost of each
in a work.
To go from one work order to the
next on a CNC machine tool the following tasks generally occurs:
The machine is down while the above
tasks are performed. These can be defined as on-line tasks.
- tearing down tool holders
- assembling tool holders
- locating and securing work
- measuring program zero
- entering offsets for program
for tool diameters and lengths
- loading the program into the
- verifying the program
- inspecting the first piece
- and, optimizing the program
the first release of a work order
Tasks performed while the machine
is producing good parts can be defined as off-line tasks. These
include programming and searching for tools, gages and fixtures for the
next work order while the machine is running. The smaller the lot
size, the harder it is to perform off-line tasks, and the fewer the
available in the overhead structure, the more tasks are performed
Based on the definition of these
tasks, setup time can be defined as the total of the on-line
Three methods of reducing setup time are:
Before starting a CNC setup time
program, first dedicate time, effort and people to evaluate and
your current setup procedures. Next, weigh the cost of implementing any
of the following recommendations to remove wasted time:
- eliminate on-line tasks
- perform on-line tasks
- facilitate on-line tasks
1. Apply CNC technology on-line.
2. Move on-line tasks off-line.
- Use a spindle probe to
automatically load work coordinate offsets for program zero
eliminating edge finders and dial indicators.
- Use a tool probe to
load tool length offsets.
- Add more memory to the
unit (MCU) to leave programs in the control.
- Background edit while the
- Prove out programs using the
3. Facilitate on-line tasks.
- Verify NC programs on a PC
download the programs to the MCU instead of using an expensive CNC
tool as a plotter.
- Organize tools, fixtures and
- Build tool assemblies during
- Dedicate preset tooling for
- Run orders in a logical
capability measurement of the machining operation process.
is a measure of whether or not the parts which the process is currently
producing are within the tolerance limits.
equals print tolerance 6 standard deviations (actual distribution).
is a measure of whether or not a process is capable of producing parts
should always be > 1.0.
should always be > 1.0.
Machining Hourly Rate
today's technology without Model-T Ford accounting practices.
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