Problems Faced by Modern Machine Shops
This CNC machinist is checking the first piece to make sure that the CNC lathe has been
programmed correctly.1
History has shown us that if a business does not adapt to changes it will not
survive. A recent example of this is the Oldsmobile Car Company which was the oldest
car company in the United States. In April Oldsmobile had to close its doors because it
had not adapted to the changes in the market.2 In the past few years modern machine
shops have noticed a shift toward ‘paperless engineering’ by their customers, and profit
margins slimming. To survive modern machine shops must have the ability to complete
orders from as large of a customer base as possible, and reduce costs. The element that is
1
2
http://www.orttool.com/equip/equip_turn.htm
http://www.cnn.com/2004/BUSINESS/04/28/oldsmobile/index.html
preventing modern machine shops from accomplishing these tasks is that these shops are
still manually programming their CNC machines.
The Problem
The practice of manually programming CNC machines in modern machine shops
is causing them to lose their profitability. This is due to the fact that manual programming
creates an inability to make certain parts, increases the amount of time taken, increases
the amount of mistakes that are made, and creates additional personnel requirements.
When manually programming a CNC machine the programmer is limited by the
number of shapes that can be cut. Ultimately this limits the range of parts that can be
produced and in addition limits the customer base. While working for a contract
manufacturing company I had the displeasure of experiencing this first hand. The
company I was working for had received an order from Boeing for a simple elliptical
ring. However when a CNC programmer attempted to program the part we discovered
that it was impossible to manually program an ellipse into the CNC machine. As a result
the business could not make the part.
The inability to program this simple elliptical ring is a clear example of how limited manual
programming really is.
Manually programming a CNC machine is very time consuming. The reason that
it takes so much time to program a part is because the programmer has to calculate by
hand the position and shape of every feature on the part in relation to the CNC machines
point of origin. This is a big problem because sometimes the customer cannot wait long
to get the parts they need, and they expect to get them on time. This was the case in
another example from the same contract manufacturing company I had worked for.
Boeing sent the company an order for a structural stiffener to go on the prototype
Comanche helicopter. Boeing needed this part as soon as possible because it was a
crucial component to the assembly of the helicopter. Since the company was still
manually programming their CNC machines it took them a long time to produce this very
complicated part. It took so long in fact that the company missed their delivery date.
Boeing was forced to send their entire assembly plant workforce home until the part was
received about a week later than planed.
It took over ten days to manually program this structural stiffener for the Comanche helicopter.
When manually programming a CNC machine it is very easy to make a mistake.
As I mentioned before a CNC programmer must calculate the position and shape of every
feature on the part by hand. If the programmer forgets to correctly account for the size of
the cutting tool, makes a trigonometry error, or hits the wrong buttons on his/her
calculator the whole part can be lost. When the programmer makes a mistake it almost
always ruins the material being used, can break the cutting tools, or even damage the
CNC machine. This can add a lot of time to a project if new material, tools, or parts must
be ordered. In addition these mistakes can eliminate the profits of an order.
Manually programming CNC machines also creates larger personnel
requirements. Since many companies are switching to ‘paperless engineering’ fewer and
fewer paper drawings are sent with an order. Instead these orders are accompanied by
digital drawings. This simple fact creates many problems for shops that are manually
programming their CNC machines. This is a problem because a CNC programmer
requires paper drawings to program a part. This forces a modern machine shop to hire
additional engineering support to create paper drawings from digital ones. In addition a
modern machine shop will also have to hire more CNC programmers since manually
programming CNC machines takes such a long time.
The Solution
The solution that I am proposing is to eliminate manual CNC programming, and
instead use computer-aided machining(CAM) software. Many modern machine shops
have already adopted this technology. One such company is Klune Industries a
manufacturer of F-22 parts. Klune uses CAM software to program all of their parts and
has profited from doing so.3 Another company that has implemented CAM software is
Batesville Tooling & Design, Inc. which specializes in manufacturing motor housings.
The CAM software allows Batesville to regularly exceed their customer’s expectations
and to keep up with changes in the market.4
The reason these companies have been so successful is because CAM software
eliminates all of the problems associated with manually programming CNC machines.
CAM software allows a modern machine shop to program very complicated parts
because it can calculate how to cut almost any shape. In addition CAM software is also
3
4
http://www.surfware.com/customers.htm
http://www.btdinc.com/companyprofile.html
very fast. Using CAM software it would have taken less than one day to program the
structural stiffener mentioned earlier. Also since CAM software automatically calculates
all of the features of a part mistakes are rarely made. Since CAM software does not
require paper drawings there is no need to hire additional engineering support. Also since
CAM is fast the CNC programmers will have more time to be working on other things,
eliminating the need for additional CNC programmers.
In order to implement this solution a modern machine shop must purchase a good
CAM software package, train the current CNC programmers, and install a Direct /
Distributed Numerical Control(DNC) system.
Purchasing a good CAM software package is probably the easiest part of the
implementation. Surfware the makers of SurfCAM have proven themselves as industry
leaders. SurfCAM costs about $20,000 but it is a very useful program.5 However
Surfware also gives the customer a lot of technical support. Through my experience I
have found Surfware’s toll free phone line to be very helpful. While I was working for
the contract manufacturing shop we were stumped trying to figure out how to program
that elliptical ring. We decided to call Surfware to see if they would help us. They
actually programmed the ring for us and we were finally able to make the part.
However without adequate training the
software is useless. There are several ways to train
the CNC programmers including sending them to a
training facility, having a expert come to the shop and
conduct training seminars, or send the CNC
programmers to a community college. This training
costs about $1000 for each CNC programmer.6
It is also necessary to connect all of the CNC
machines to a DNC server. One such system is called Predator DNC made by Predator
Software, Inc. This system allows connections between the CAM software and the CNC
machines. In addition it allows a modern machine shop to save old programs from the
5
6
http://www.surfware.com/profile.htm
http://www.camscorp.com/cnc_training.htm
CNC machines to a server instead of unreliable floppy disks.7 This systems costs about
$3000 for the hardware and software.
Conclusion
In conclusion it is evident that modern machine shops cannot remain profitable
while they are manually programming their CNC machines. With manual programming a
business will be losing customers, and their costs will be soaring. However with CAM
software a modern machine shop will be able to make more complicated parts, meet strict
timetables, eliminate programmer errors, and eliminate the need for additional personnel.
7
http://www.predator-software.com/dnc.htm