Time and quality influence Mesh Gear to invest in five-axis capabilities

“The modern flexible machine tool provides a machining operation with the ability to exceed customer expectations on quality, part accuracy and lead times. In a niche market like gear manufacturing, the space that we operate in, the advantage goes to the company that seizes each opportunity when it comes to new technology and then takes the decision to implement it into their production process,” said Trevor Clayton, a director and one of two brothers that have joined the family business started by dad Mike in 1976.

Mesh Gear specialises in the manufacture of gears, associated components and an array of other industrial consumables on a production basis for the local as well as international heavy equipment industry such as the mining, construction, agricultural, railway, military and industrial sectors.

18 months ago Mesh Gear installed their first 5-axis CNC machine. A second was installed in November 2017

“The manufacture of industrial power drive componentry which can be used in the world market requires machinery and proven processes which can achieve and maintain these world standards on a consistent basis. This, along with the ability to control the complete manufacturing process from start to finish at your own premises under one roof, is what allows Mesh Gear to achieve and maintain these high standards. Having total control over all heat treatment processes from normalising, annealing, conditioning, stress relieving, carburising, nitriding, tempering and press quenching is what sets Mesh Gear apart.”

“This along with our own metallurgical laboratory and metallurgist, allows us to continuously monitor and verify that we are achieving our customers heat treatment and metallurgical requirements.”

“Since the economic downturn in 2009, Mesh Gear has been on a drive to increase and diversify our customer and product base. At the same time we have been introducing new machinery, to improve the quality and productive efficiency to our then current customer base.”

“With this expansion and consolidation comes the inevitable need to invest in your manufacturing processes.”

Gear grinding
“Mesh Gear had to ensure that we improved on our gear grinding abilities. Gear grinding is usually employed as the final machining process when manufacturing a high-precision gear. We had to ensure that we catered for both high volume gear grinding for the automotive and heavy equipment industries, as well as the smaller volume larger gear grinding requirements for the mining, rail and industrial client base.”

The machine has been used for the final machining of gears in a soft state as well as in a hardened state if required after heat treatment

“In order to address our high volume gear grinding demands, we imported two new gear grinding machines with the latest technology from Germany.”

“The new machines are equipped with the latest CNC controls, a dialog-driven user interface, digital drives and a newly developed profiling unit. The new machines are universal machines for grinding gears and pinion shafts and are used by manufacturers from the automotive, agricultural, construction, machine tools, mining, aircraft, textile as well as a variety of other industries. They can be used for individual production, small-scale production as well as for mass production.”

In order to cater for the larger sized gear grinding requirements, two Hofler gear grinders were also imported. These are capable of grinding up to 1000mm in diameter and also allow for gear tooth profile correction if required by the customer. We are also capable of running all four of these gear tooth grinders on two shifts, which allows for additional capacity if required by our customers when demand goes up.”

One of the two new gear grinding machines that Mesh Gear has invested in

“These gear tooth grinders are also verified continuously to ensure they are achieving the required AGMA standards. These include involute and parallelism profile checks as well as 100% checks on the surface finish of the teeth. All components are thoroughly checked by our quality team before being dispatched to our customers.”

“We also invested in a worm/thread grinding machine, which removes the distortion in the worm shaft after heat treatment and due to the far smoother finish, allows for a far longer life in the worm drive unit.”

CNC turning and milling
“Over the years we have been continuously increasing the number of machines in the CNC turning and machining department. We feel this is the engine room of the business as it feeds through to all the other departments. The latest to arrive, installed earlier this year, is a Victor V-Turn 26 CNC lathe. Another Victor CNC lathe is on order and will be installed in early 2018. This now takes it to over 20 machines in this department.”

“But our biggest and most significant investments were still to come.”

5-axis move
“The 5-axis CNC machine tool is the mainstay on many machining shop floors internationally but not so in South Africa. Local companies prefer 3-axis CNC machines, but this is changing. While these 5-axis systems were once reserved for undertaking complicated and specialised applications, large and small manufacturers now realise the value in using a 5-axis machine for a variety of projects. Many of them have been able to minimise lead times, bolster accuracy and efficiency, and improve profitability as a result.”

A gear on the gear grinding machine

“12 years ago we started manufacturing bevel gears (crown wheel and pinions). We eventually ended up with seven bevel gear generators. However, even with controlling the distortion in heat treatment through a lengthy heat treatment process and press quenching we were still getting up to 0,10 – 0,20mm distortion. This may seem like very little, but when the bevel wheel and pinion were put back on the roll tester and blued, the change in contact pattern was noticeable and limited the interchangeability. This forced us to rethink our strategy on how we manufacture the bevel gears and the 5-axis route was certainly the one to take.”

“Although they remain costly in terms of capital investment, 5-axis machine tools offer the opportunity to save on setup and production time and costs. These factors influence your decision and make a difference to the speed of the return on investment.”

“18 months ago our first 5-axis machine was installed. We chose a 5-axis machining center that has XYZ travels of 950 x 850 x 650mm, can take a table load of 1 000 kilograms and has a 20kW motor.”

Mesh Gear specialises in the manufacture of gears and associated components on a production basis for the local as well as international heavy equipment industry such as the mining, construction, agricultural, railway, military and industrial sectors

“The machine has been used for the final machining of gears in a soft state as well as in a hardened state if required after heat treatment.”

“We have achieved dramatic time saving on real time machining of spiral and straight bevel gears so we have invested in another 5-axis machine but this time a universal machining center, which was installed in November 2017.”

“Again the machine is alleviating bottlenecks for the milling of spiral and straight bevel gears. An added advantage is that we can now offer 5-axis milling for other components that our clients require.”

“Highlights of this new machine is that it has a XYZ axis work area of 650 x 520 x 475mm, XYZ rapid traverses of 42m/min, a table work surface of 630 x 500mm and take a load of up to 300 kilograms.”

“It must however be remembered that the 5-axis machine is not the complete answer to your straight and spiral bevel gear (crown wheel and pinion) problems. There are up to 10 important processes to be considered when making these parts, with heat treatment and distortion control still being the most important, however, 5-axis machining has definitely helped in improving the end product and allows for the interchangeability that the customers require.”

Eliminating distortion in gear manufacture
“There is a long list of factors to consider when heat treating gears. High performance steel components are usually heat treated at the end of the production process in order to obtain an optimal functional performance. However, in nearly all cases, this final heat treatment also leads to distortion, which means a change in dimensions and shape of the part. If the deviations exceed the permissible tolerances, the components have to be reworked. Since these corrective measures have to be taken in the hardened state, high additional costs occur.”

“Over the years we have invested substantially in our quenching and heat treatment processes and are unique in that we are one of the few gear manufacturers that have these facilities and processes on site.”

Over the years Mesh Gear have been increasing the machines in the CNC turning and machining department. The latest to arrive, installed earlier this year, is a Victor V-Turn 26 CNC lathe. Another Victor CNC lathe is on order and will be installed in early 2018

“Our in-house heat treatment facility consists of two gas carburising furnaces and one gas nitriding furnace, all of which are fully automated and programmable. A number of other furnaces and a quenching press are also required and are in place for heat treating bevel gears. The above is well backed up by our heat treatment laboratory (metallurgical, case depth and hardness testing) and a qualified metallurgist.”

“This allows us to cover the following heat treatment processes in-house: annealing, normalising, conditioning, stress relieving, gas carburising, gas nitriding, tempering and press quenching.”

“Distortion in gear manufacture is universally a huge headache and if you do not control the processes in-house, it is going to be inconsistent and costly.

“Our investment in new equipment is already paying dividends. Not only with the resultant process time saving and quality improvements, but also with the additional interest from new clients as word gets out about what Mesh Gear is able to offer the mining, construction, agricultural, railway, military and industrial sectors.”

For further details contact Mesh Gear Manufacturers on TEL: 031 461 1121 or visit www.meshgear.co.za