The market for new cars in Southeast Asia over the next two years is set to grow significantly. According to a recent global survey by the market research company Nielson, while consumers in Southeast Asia currently have some of the lowest levels of car ownership globally, they also have some of the highest intentions to purchase a new car within the next two years. 

Even for those who already own a car, the aspiration of Southeast Asians to upgrade their existing vehicles is significantly higher than the global average. This desire for a new car is being facilitated by rising income levels in the region as more and more people are making it into the middle class. 

This high demand for cars will mean an inevitable knock-on requirement for one of the most important automotive components — the gear. Local gear manufacturers will need to ramp up their production to meet this increased demand by becoming more productive and efficient — process integration is one of the key ways in which the gear cutting industry is doing so.

The concept of process integration involves the bringing together of a large number of individual machining processes into a smaller number of multi-functional machines. As this article will show, this has both a number of benefits as well as few limitations. This article covers both the benefits and limitations of process integration with a focus on gear manufacturing and will present two case studies to illustrate.

Benefits Of Process Integration In Gear Production

The high demand for cars leads to the need to manufacture more gears and gear manufacturers will now need to be more productive and efficient.

Process integration presents a number of benefits for gear manufacturing. The first, and most obvious of these is the fact that fewer individual machines will be required. This can often mean a significant saving for manufacturers in terms of capital expenditure as, generally speaking, two or three individual machines will often work out to be more expensive than a single multi-functional machine. 

For example, turning, grinding and gear cutting processes can quite easily be combined onto a single machine base. Other commonly associated savings from process integration include lower automation costs, reduced total part through-put time, reduced set-up time and staff required due to a lower number of clampings/set-ups, as well as a reduced floor space requirement (in terms of both machine footprint as well as parts storage space). In terms of part quality, as process integration leads to a lower number of required part clampings, this in turn means a reduced chance of compound errors being generated. 

Risks Of Process Integration In Gear Production

Despite this, process integration is not without its risks and will not always be the recommended strategy. Whether it is or not depends on a number of company- and workpiece-specific factors. These include the specific workpiece geometry, the batch size and repetition of the workpieces, company-specific logistics concepts, and the requirement to react to unforeseen changes. 

These unforeseen changes can include the quantities that need to be produced, the specific workpiece, the cycle time, the quality and the process. A more integrated process could lead to a reduction in a manufacture’s ability to respond to these issues. These need to be balanced against the benefits of process integration. In deciding whether to implement process integration, and to what extent, this requires working closely with the machine tool builder to consider all the related factors. 

The following two case studies present real examples of when process integration has and has not been an effective strategy for individual gear manufacturers. 

Case Study 1

The engineers at Emag Koepfer were approached by the manufacturer of a lean shaft for an electric powertool. The idea was to do both turning and hobbing on one machine — known as ‘hobbing from the bar’. The expectation was that this would lead to a reduction in the investment costs for the turning and hobbing operations, reduce set-up and cycle times, and deliver a shorter ‘through the shop’ time for the parts. The initial thought was: “let’s develop a machine to hob and turn from the bar.” However, it was not quite as simple as first imagined. The engineers needed to consider the variety of the different shaft variants that needed to be machined and their geometric complexity (geometry, knurls etc.).  

Results 

It turned out that after investigating the possibility of developing such a machine, its cycle times and required machining axes for turning, hobbing and knurling were significantly different for the various complex shafts that the manufacturer wanted to produce. While the engineers could certainly have developed such a machine, it was determined that a dedicated machine to ‘hob from the bar’ would not be cost effective. Despite this, the situation led the engineers working on this project to develop a brand new process known as ‘dry free hobbing’, which has since revolutionised the manufacturing of armature shafts. 

Case Study 2

Process integration allows fewer individual machines to be used.

• Two turning machines
• One gear hobbing machine
• One hardening machine
• One milling centre
• One grinding machine 

The task that the engineers were faced with was to develop a process that would use just two automated pick-up multifunctional machines that could do the turning, boring, gear hobbing, measuring and grinding operations (everything except for the hardening). 

A study of the manufacturer’s original process indicated that the loading and unloading times for the total process added up to 117 minutes and that total cycle time came to 96 minutes. With the newly developed two-machine process, the cycle time remained the same at 96 minutes; however, the total loading and unloading time was reduced to just 10 minutes, a saving of 107 minutes. A comparison of the old and new ‘time through the workshop’ for the parts, which includes storage and transportation time, showed a reduction from the previous 169 hours to just 56 hours. 

Making The Right Choice

What is clear from the above examples is that process integration for gear manufacturing is a highly complicated issue. Numerous factors need to be considered to fully determine the optimal level to which processes should be integrated. 

There are a number of clear benefits that manufacturers can potentially achieve; however, due to the complexity, each individual case needs to be carefully analysed with the manufacturer and the machine tool company working together closely. 

When faced with a range of potential process arrangements, each competing option should be analysed based on considerations of the final cost-per-part based on the individual full-cost factors of each machine, as well as the company’s desire for future flexibility and versatility. If a professional analysis of the gear manufacturing process is conducted, then manufacturers can potentially realise the significant efficiency gains that are required to succeed in today’s competitive environment.