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Tool Life Increase
A forging manufacture with multiple tooling issues were evaluated and solved in a few months duration. It was quickly
noticed that forge tool geometry needed modification. The tooling creation process was evaluated and the appropriate coating
& heat treating were changed. There was a significant modification made to the forging presses. A critical heat transfer
condition was corrected. All of these changes were minor in the scope of daily operations and cost to the production facility.
The result of these changes was a 26% drop in annual tooling costs, while achieving an increase in product quality. The
uptime of the presses were improved as the perishable tool life increased. The semi-perishable tooling and bolster usage
reduced by 50% as they were not cracking or breaking.
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Forge Lube Recycling
A client was concerned with the waste disposal of their graphite based forging lubricant and we evaluated their tribological
process. Due to the type of forging and flow characteristics of their material their lubricant was a good match for recycling.
After investigation we advised the recycling of the oil-graphite lubricant and concentrated on reducing the amount of waste.
With some simple and economical processes the used lubricant was returned to service at a significant reduction in cost and
waste. Most forging lubricants are recyclable to some degree.
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Reverse Engineering
A manufacturer had a coldform press break-down and needed a main drive component replaced quickly. The replacement part
from the original equipment manufacture (OEM) was expensive but more importantly had a 12 week lead-time.
After evaluation a print was created using the original component while considering it's application. The material was
determined and sourced along with the proper heat treatment. We utilized one of our proven vendors and established a quick
priority for completion. The press was back up and running production within one week of failure and the cost was half of
the OEM.
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Another manufacturing company had a large press break down as a result of some clutch components failing. The failure
was concentrated on two 4" diameter locating pins. From our metallurgical evaluation we determined that these pins required
a special heat treatment not easily sourced at the time. We sourced the pin material, specified the heat treatment, and evaluated
a special heat treating supplier. We made arrangements to ensure the pins were heat treated correctly the first time at the
supplier level as reduction to lead-time was critical. All activities, including shipping determined the press be down for
10 days. Another situation were the OEM price was high but the main reason to bypass them was a long (14 week) lead-time.
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The Maintenance Manager of a forging company was concerned about the up-time of his machinery and asked us to evaluate
his operation. We determined that his company did not currently need our services as the presses in question were fairly
new with no break-downs of any kind. During our report he directed our attention to the OEM recommended spare parts list.
This list of parts the company didn't purchase because of high cost.
Using the list as a guide and re-evaluating the presses we developed a long-term component replacement strategy. After
selecting semi-perishable tooling expected to cause future maintenance issues, a scheduled downtime was coordinated with our
reverse engineering activities. We had complete prints designed and drafted of all the potentially needed tools. Then working
with their restrictive budget, only manufactured those tools that would be required inside an 18 month time-frame. These
tools were added to their tool crib. The other reverse-engineered prints were waiting, at the ready, until they needed them.
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Press Machine Rebuild
In the function of project manager we performed a rebuild to a five station Waterbury Farrel Partsformer, often called
a cold-header or cold-former. The machine was rebuilt without removing it from the production facility to reduce cost and
lead-time. The ram, eccentric crank, pittman arm, cams, star wheel feed clutch, transfer system, cutter system, perishable
and semi-perishable tooling were removed and re-worked. Some new systems were added such as: lubrication, die force monitoring,
and pneumatic wire clamping. The press was re-assembled and ran off to new machine specifications with a Cpk of 2.69 making
precision forgings; the press was over 30 years old.
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Forge Tool Design Software
A Hatebur press is one of the most intriguing forging machines that we have worked with. Built in Switzerland by Sulzer
and designed by Hatebur. These presses are horizontal multi station forging machines. The AMP-70XL Hot-matic is rated at
1500 metric tons and can produce up to 80 parts per minute. Press adjustments allow forging a variety of part sizes and shapes.
Some of the adjustments based on the crank angle of the eccentric are: opening and closing of transfer grippers, actuation
of die ejectors, actuation of 2nd 3rd and 4th station punch ejectors, and cut-off finger opening. These presses are also
designed to allow closed die, open die, piercing, spray water cooling, and trimming processes.
The forged part is held the entire time it is moving through the progressive four station forming operation, from bar
stock to complete forged part. If the part isn't firmly held in this horizontal press then it will fall and either crash
or trip a load monitor and stop production.
The Hatebur press is highly adjustable to allow working with parts of differing sizes. To efficiently utilize these adjustments,
Hatebur has established plotted prints or charted movements of the adjustments based on the main eccentric crank angle (timing).
These adjustments and other components get move based on their connection to the main crank of the press and cycle for each
ram stroke.
The Tooling Engineer has to use these timing charts to create a tool design. If the timing plots are not used, the tool
design will fail. It can take 4 to 10 hours to design a concept progression which synchronizes with the press. This design
may not forge well, if changes are needed then a tool redesign can take another 2 to 3 hours. It depends on the staff's capabilities
and if the forging is unfamiliar. For new forgings it normally takes 3 to 8 iterations to be able to finalize a progression
concept. Next the engineer has to produce a set of prints for a machine shop to make the first tool package, then start testing
them on the press. At the press, changes are made to to make the progression forge correctly and a tool redesign is needed
and another 2 to 5 hours will be required to re-visit the timing charts.
The time consuming chore of interfacing with timing charts can be reduced to a few keystrokes; significantly shortening
the duration of tool design. We have developed a software package that incorporates the press timing charts and tool design
parameters. To design from one station to the next and obtain all the information as one would get in the traditional way,
you enter your design data (maybe 20 keystrokes max) engage the solution button and the unknown variables are solved. The
time it takes to test different parameters (ie: diameters, gripper lengths, penetrations, and grippers start-opening) can
take minutes, not hours.
Designs can be performed in a "what if" fashion where the design variables can be tested or changed quickly
and easily. Engineers can concentrate on the forging process rather that the tedious timing charts that the machine must
adhere to. The machine parameters calculated by the software include: total horizontal way, crank angle at grippers start
opening, punch clearance or no crash, gripper stroke opening, die penetration, crank angle at grippers start closing, and
gripper length. Of course these terms are created by Hatebur, the software can solve any plotted or mathematical problem.
The main advantages of the software system are to reduce design time to minutes, eliminate error of interfacing with plotted
timing charts or tables, and focus attention on design of tooling. Another benefit is the elimination of mistakes that can
occur with using worn out charts or simple user error. This software allows for a discrete and virtually permanent copy of
the main machine movement prints to be securely kept. In the event that the press components wear and the original main machine
prints are no longer valid, the software can accommodate a change. If a press is rebuilt the chances of the original prints
being valid are not likely, this software can help to restore the timing diagrams. The program is accurate, precise, and
easy to use and understand; all variables are viewable on one computer screen.
The software package is also programmed to quickly design all the parameters of the Hatebur complicated ejector with ejector
sleeve and the tedious piercing die stackup. All the calculations can be accurately and quickly completed.
Press operators can also use software to determine volumetric changes of punch into die penetration from changes in cut-off
length for closed die forging. Any machine or tooling parameter that can be plotted or mathematically defined can be programmed
and solved with this software package.
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Developments in Forging Tools
For half a century there have been many developments in tool steel, from alloys to processing, they are still viable today
if applied correctly. Through the proper use of tool steels we have multiplied tool life, increased quality and reduced costs.
Carbide has been used for a few decades and has significant improvement in properties over tool steel, depending on the
application. We have applied carbide to multiply tool life (10 times is normal) with the expected lower tool costs. When
carbide is applied as die inserts, the necessary calculations must be performed to establish a good design.
In the last decade ceramic has been used for tooling with multiple increase in tool life. In general, ceramic has higher
wear resistance and is more brittle than carbide, thus requires mathematical calculation to prove it is applied correctly.
Ceramic has been well established as a die insert material for increasing hot forging tool life.
During production many forging companies experience problems with tooling where the cause isn't apparent, after replacing
tooling they eventually wind up with the problem returning. Solutions can be granted with: material selection & processing,
tool & part geometry, lubrication, heat transfer, coatings, process speed & velocity, and tool processing. Which
to apply is usually based on experience.
We have many years experience at solving these problems and excel at eliminating or reducing them.
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