Aluminuim tool

When I was in the aerospace industry, we would apply hard-coat anodize to aluminum surfaces so we could use OD grinders on aluminum parts. Chip control is another typical problem with rolled, forged and extruded alloys. In short, forming a chip is easy, but it can be difficult to break the chip, resulting in long, stringy ones that wrap around tools and parts. Cutting tool geometries have advanced significantly in recent years, but light depths of cut and high cutting speeds still can create issues with continuous chip formation.

Eliminating stringy chips may require altering cutting speeds, chip loads and tool geometries. Continuous chips are a substantial hindrance to achieving optimal cycle times. Development of machine tools, cutting tools and machining techniques specifically for aluminum has advanced quickly since the s, and several machine tool builders have placed machines on the market expressly designed for machining aluminum. When paired with advanced cutting tools, the combination can create huge volumes of aluminum chips.

If they are not removed from a work area, bad things might happen. Commonly known as re-cutting, chips can be drawn in by a cutting tool and become trapped between the tool and part, causing poor surface finish, tool breakage and increased tool wear.

Manufacturers have employed high-pressure coolant to blast chips out of the cutting zone and applied high-volume flood systems to wash chips out of the machine. The volume of chips from these machines is so great that machine tool designs had to change so gravity could be used to help evacuate chips. Some vertical lathes have been reversed so their chucks are above the cutting tools, forcing chips to fall away from parts.

Aluminum also has a propensity for chip welding, or adhering to the edge of a cutting tool. Chip welding alters tool geometry, which exacerbates the welding problem and creates a chain reaction that typically results in tool failure.

A fuzzy or melted-looking surface finish is the primary indicator of chip welding. Well-formed aluminum chips should be very shiny and smooth on one side and have a frosted appearance on the other. This indicates that chips are sliding across the face of the tool uninhibited. If a chip is fuzzy and white on both sides, chip welding likely has occurred. Correct cutting speeds, suitable coolant, properly prepared cutting tools and good process development are needed to combat chip welding.

Aluminum automotive parts often are made by die casting, and automakers use enormous quantities of die-cast aluminum. Although it is fast and accurate and creates near-net-shape parts, machining is frequently required to ensure proper mechanical fitment.

The alloying chemicals used to create die-casting alloys make the materials extremely abrasive and can wreak havoc on cutting tools.

The use of high-speed steel is not even a consideration when machining die-cast parts, and carbide tools usually are used only when necessary. Machining die-cast alloys requires polycrystalline diamond tools. These tools then are lapped to create the desired geometry. Two significant characteristics make PCD ideal for machining aluminum.

PCD is the most wear-resistant substance used for cutting tool manufacturing and is highly resistant to chip welding. Machining high-volume automotive parts in autonomous cells demands the use of PCD tools. As you may guess, PCD tools are very expensive and almost always custom-engineered for a specific application. PCD is capable of working at extremely high speeds.

It is also the first choice when finishing close-tolerance parts because aluminum does not weld to the cutting edge. Chip welding is the primary cause of poor surface finish and the inability to hold tight tolerances. Aluminum can present challenges, but machine tool and cutting tool manufacturers have made significant advances in the past two decades. Becoming efficient requires understanding available technologies and balancing costs with production quantities.

There are amazing videos of machining aluminum on the internet. Check them out, and see how fast a well-designed process can move aluminum. For more information about machining aluminum, view a video presentation at cteplus. All about aluminum. Author Christopher Tate Published. Related Glossary Terms abrasive abrasive Substance used for grinding, honing, lapping, superfinishing and polishing. See jig; modular fixturing. Challenges Although machining aluminum can be easy, the characteristics that make it simple to machine may pose challenges, especially when presented with high production quantities, stringent cycle requirements and close tolerances.

Christopher Tate. Christopher Tate is facilities operation director at EthosEnergy in Houston. Their individual process can impact the cycle time. For example, some injection molders are looking at lowest cost tooling up front and not considering the piece part cost over the lifecycle of the production run.

This can greatly impact cycle time. If using valve gates you can reduce cycle time and increase the process window, but they cost more up front. One molder may use valve gates whenever possible and another may not at all. The savings in tooling and a drop in cycle times will produce parts quicker. Another benefit is that it is easier to cut aluminum than steel. The major learning curve lies with the molder to teach their people to take care of the tooling and be gentle with it.

As for the longevity of aluminum tooling, Jones points out that he has some tools still running with well over , shots on them. In the past the mainstay was prototype tooling. You would get 50, maybe 1, parts for all the testing and different departments and then build a steel production tool. Today aluminum tooling is being used for 50,, , and even , shots for production.

The average will depend on the demand. Throw into the mix modern surface coatings that can extend the aluminum tool life and you have yet one more thing to consider in the decision-making process. Mike Kleinert, Vice President of W. However, when you get into higher volumes with more abrasive materials e. To guarantee an aluminum tool for so many pieces I would say is a risky statement.

As for running an aluminum tool, Kleinert believes a little bit of vigilance goes a long way. It needs to be watched a little more than normal. It does require some additional awareness, but that is the case whether using aluminum or steel. Things can happen with either material, and the operator needs to be aware of what he is doing.

I think it is a great idea that all parties involved work collectively as a whole—that could save any finger-pointing later and ensure the molder is going to be more aware of what he will be receiving. The mills are working on improving the welding process for the series material, but still the current practices are acceptable.

See Myths Sidebar for some common myths about aluminum tooling. It seems about a decade ago there was a similar buzz in our industry.

The major differences today are that new aluminum grades have increased performance and reliability, faster machines and software are available for designing and producing the molds, and a better understanding of the requirements of aluminum tooling and knowing the production goals give mold manufacturers a better direction.

Currently when molding with aluminum tooling the most common solution for a runner system is the cold runner, Oles explains. In most cases, the added value of having a similar process in prototype and production can be significant but not considered.

To offset the cost of a hot runner manifold system, early communication and planning can allow the hot runner system to be recycled from the aluminum prototype tool into steel production tooling. Using valve gates increases cost but opens up the processing window and can reduce cycle times. Using a nozzle sleeve or cooling bushing as a thermal isolation barrier is one method to prevent nozzle tips from freezing off, Oles adds see Figure 4.

By warming the gate point area it decreases the delta in temperature from the bushing to the nozzle tip. The result is easier and consistent start-ups for molding.