CAD/CAM Insight

FeatureCAM 2009 will support slant turning on mill-turn machines.

Delcam has been increasing its business in the aerospace industry for the last 10 years or so. The company originated from research at Cambridge University in the 1960s and was formally founded in 1977, so 10 years is less than one-third of its history.

Until 2000 toolmaking was by far Delcam’s biggest priority. This was mainly the manufacture of injection molds for plastics, but also included other types of molds, patternmaking, press tools, and die-casting equipment.

The automotive industry provided the main source of business, although the company had a significant number of customers making tooling for the aerospace industry.

Since 2000 Delcam has put a lot of effort into diversifying.  

Usually aerospace companies simply bought the CAM system that went with its choice of design software. Lately companies have been under pressure to increase efficiency, and so have started to look at their CAM requirements more closely. Many people have been surprised at how much more productive dedicated CAM software can be than the design bolt-ons that they have used in the past. It is not unusual to be able to halve the machining time for a complex part, which is effectively the same as doubling the productivity of the machine tool.

A change in the structure of the industry has reinforced this need for change.

Until recently, a significant proportion of manufacturing was undertaken within the large aerospace companies.

However, both Boeing and Airbus have been divesting manufacturing operations to concentrate on product design and assembly. The divested companies no longer have the same level of assurance that they will receive particular manufacturing projects. They need to boost their productivity to compete with other potential suppliers and so must ensure that they have the most effective CAM system.

Complex Machining Strategies

Companies are looking at more focused CAM suppliers also because there has been more focus on complex machining concepts like five-axis .

Five-axis machining is absolutely critical for aerospace companies making anything other than the very simplest components. The benefits of five-axis machining come in two main areas.

Clive Martell, Managing Director, Delcam

First, the number of setups required to produce a part can be reduced dramatically. Most parts can be completed in one or two setups on a five-axis machine.

The same part might take six, seven, or more setups on a three-axis machine. Fewer setups can produce significant time savings, both in terms of the overall machining time and in the amount of human intervention required to complete the part.

Reducing the number of setups also helps to maintain accuracy as every new setup is a potential source of error. Even simple operations like drilling can see time savings.

With a three-axis machine, every hole at a different orientation requires its own setup. With a five-axis machine, the complete series of holes can be drilled in one operation.

The second advantage of a five-axis machine is the ability to use shorter cutters. This is possible because the head of the machine can be oriented toward the surface to be machined and so allow access with a shorter cutter.

Five-axis machines are becoming increasingly common in the aerospace industry, even among relatively small subcontractors.

Benefits of Multitasking

Mill-turn and other multitasking machines offer a similar benefit to five-axis machines because they allow complete parts to be produced in one operation that would otherwise require multiple setups.

If anything, the benefits are even greater, because parts can also be produced on a single machine that would previously have needed a number of different pieces of equipment.

Machining of solid models is not such a significant development, as most CAM systems are equally capable of producing accurate parts regardless of whether the original data is supplied as a solid model or as a surface model. More important is the speed with which modern machine tools can produce parts from a solid billet of material.

This has come about partly because of the increased machining speeds that are possible with modern control systems and cutting tools. More significant, however, is the ability of modern machine tools to produce complex parts in a single setup. The overall effect of these time savings is to make it practical to machine short runs of parts from a solid that would otherwise have to be cast or forged.

Improved simulation in CAM systems has been an important aid in the introduction of the more sophisticated five-axis and multitasking machines. With a three-axis machine, it is fairly easy to visualize what will happen when the program is run on the machine. This is much more difficult with a five-axis machine, especially when trying to predict motions like axis reversals that might leave a dwell mark on the part.

When moving on to multispindle machines, the degree of complexity increases still further. Many of these machines produce long runs of parts, so every second is vital in the cycle time. Trying to synchronize the different operations on the various spindles and, at the same time, to minimize the overall machining time and prevent collisions would be virtually impossible without the ability to simulate the movement of the machine on the computer.

Both suppliers and customers are realizing that no single solution exists for the machining needs of all the different types of companies out there. In particular, there is a clear distinction between the needs of toolmaking companies and production-machining companies.

This means that CAM suppliers must be able to offer at least two different programs to meet the needs of these two types of customer. In most cases, it is easier for companies to acquire the type of program that they don’t have than it is for them to develop something from scratch.

Today’s Manufacturing Climate

Of course, the current economic downturn will make it even harder for some of the small companies to survive, especially those specializing in a single industry or those selling in a limited geographic area.

Today the current climate for manufacturing is mixed. The problems in the construction and automotive industries have been well-documented. However, in other areas things are much more positive.

The concerns over the aerospace industry that were raised last year as fuel prices increased seem to be receding. However, the defense side of the industry may not be quite as strong.

Luxury-goods markets, such as the private marine industry, will also have a harder time, although many of the people buying these types of products seem to be immune to any general downturn in the economy. On a more positive note, the medical and dental industries seem set for continued growth as the population ages. Both these industries are now using CAM and other automated manufacturing tools to a much greater extent.

In some ways, a tighter economy can help sales of CAM software. In good times, it is simpler for companies to take the easy option to increase output - buying more machines.

With borrowing money becoming more difficult, those same companies will need to focus on increasing the productivity of their existing equipment. This might be through upgrading the machine tool control, investing in high-speed cutting tools, or by introducing a more sophisticated CAM system that will allow them to boost the productivity of both their programming staff and their machine tools.

For more information, visit www.delcam.com.