The vast majority of people working with CNC machine tools are
operators - entry level people who run CNC machines day-in and day-out.
If you are a CNC operator, someone else will program and setup your machine.
Tasks you perform are limited to loading and unloading parts, making
adjustments during the production run to maintain workpiece size, and replacing
dull cutting tools. While these are extremely important tasks in any company,
you may be one of the many operators that aspire to do more - for your company
and especially for yourself.
The next logical career advancement step for a CNC operator is to become a
CNC setup person. This is a person who can completely setup and machine
production workpieces for the jobs they are assigned - without needing any
help. Though another person is still supplying the programs, a setup person -
more correctly called a CNC machinist - will perform all tasks related
to getting the machine up and running. If required, a setup person can also
complete the production run (though many companies will turn the machine over
to a CNC operator once the setup is completed).
Are you trying to upgrade your work-force?
Progressive managers are always looking for ways to improve the proficiency
of their staff. Considering the fact that most entry-level CNC people are
hired-in with little or no previous manufacturing (let alone CNC) experience,
CNC-using companies are usually on their own train people from scratch. Many
have done a pretty good job when it comes to providing training for basic
skills that CNC operators require - skills like blueprint reading,
tolerance interpretation, gauging, and shop math - to name a few.
The best CNC operators are eventually promoted to become setup people. Yet
little is available to help you provide the training necessary to help them go
from simply maintaining production to making their own setups. This book
provides key information required to bridge the gap. Why not get a copy to keep
in your company's library? Better yet - why not supply each of your aspiring
operators with a copy of their own?
Specific setup-related tasks addressed by this book
This important 14-chapter guide presents setup-related concepts for CNC
lathes (turning centers) from the ground up. While it assumes the reader has
some experience actually running a CNC lathe, it provides comprehensive
explanations of what it takes to make setups.
Preparation and organization
A setup person must be prepared to make even the simplest setups. Related
tasks include gathering components and understanding setup documentation.
Preparation tasks are presented in chapters 1, 3, and 10.
Cutting tools
A setup person must assemble and place the cutting tools used in the setup.
These tasks are discussed in chapter 3.
Workholding setup
A setup person must ensure that the workpiece being machined is properly
held and supported. Specific tasks include placement of top tooling (jaws) on
2-, 3-, or 4-jaw chucks or collets in collet chucks, the machining of soft jaws
or collets, and possibly the placement of work support device in a tailstock.
These tasks are described in chapters 4 and 5.
Program zero assignment
In most companies, the setup person is expected to align each program's
motion commands with the setup that has been made. In essence, the setup person
must establish an origin point for each tool. Specific tasks vary based upon
cutting tool type. These tasks are described in detail in chapters 6, 7, and 8.
Sizing the first workpiece
During the machining of the first workpiece, the setup person must ensure
that each tool is cutting properly. Of extreme importance is making sure the
tool is machining the workpiece within its tolerance band. Most setup people
use wear offsets to make these minor adjustments. Wear offsets are covered in
chapter 9.
Verifying the program
Especially important for new programs, a setup person must confirm the
correctness of any program they run. Mistakes in the program, of course, could
be disastrous. Program verification techniques are discussed in chapter 11.
Quality control
Setup people are often responsible for first workpiece inspection
(though some companies do have other people responsible for this task).
Regardless of who actually performs the first workpiece inspection, the setup
person is usually responsible for maintaining quality control documentation for
the jobs they set up. Quality is the topic for chapter 12.
Chapter headings:
1 - Getting prepared - What equipment will I need?
2 - Overview of a CNC lathe
3 - Development and utilization of set-up sheet
4 - Selection of workholding method
5 - Machining of collets and jaws
6 - Establishing zero in the X axis for center drill, drills and end mills\
7 - Datum / work shift setting
8 - Geometry offsets: What are they? How are they established?
9 - Wear offsets: What are they? / How do you use them?
10 - Setting up the safe index position
11 - Proving out the program
12 - Quality - be quality conscious - always
13 - Handy stuff -reference material
14 - Safety first
A note from the authors
One of the most neglected areas of study for people entering the machining
trade is related to setting up CNC turning equipment. The knowledge and ability
to bridge the gap between the CNC program and the machining of an acceptable
workpiece is essential to becoming a capable machinist. Truly, a good setup
person marries the CNC program to the CNC machine being run. This book will
lead you through the complete process of setting up a CNC lathe.
We have tried to cover everything that will affect your ability to
successfully accomplish the task of CNC lathe setup. We purposely stay away
from delving deeply into programming a workpiece. There are numerous
avenues available for people wanting to become CNC programmers, including
several of the products available from this website.
Additionally, we do not go deeply into cutting tools and their applications.
Again, there are many books written on this topic. And most cutting tool
suppliers provide a wealth of technical information regarding the cutting tools
they sell.
We have made a effort to give you a real appreciation for the CNC machine
tool, it’s components, and how they are tied together. We want you to know
“why” certain things happen and “where” answers can be
found. While it may be possible to learn how to setup a CNC lathe through
repetition alone - and this may be acceptable as long as you are content to
limit your focus to specific machines, parts, and processes - it is much more
rewarding to extend your capabilities by truly learning the related tasks in
detail.
