Howells on track to success with ITC

FOUNDED IN 1946 as a radio and TV repair shop, Howells Railway Products has travelled a long journey since its early days. The business grew from a small shop to one of the largest producers of coils and transformers in Manchester. 

The rail experts manufacture everything from transformers and rectifiers, impedance bonds, tubular stretcher bars, disconnection boxes, AWS magnets, railway signals, overhead lines and much more. To efficiently machine such a diverse range of products in varying quantities, Howells Railway has worked with ITC since 2018.

Initially having issues with tool life and performance in some of its processes, a relationship with ITC was formed and the Tamworth cutting tool manufacturer instantly made an impact. ITC introduced its solid carbide end mills and drills to deliver tool life improvements and cost benefits across a wide range of applications. This was then increased to turning products which again offered a competitive alternative to the existing tools being used on site.

Reducing costs 

From this early success, ITC's Gary Murrey then introduced the WIDIA line of indexable cutting tools with modular drills and high-feed shell mills being trialled on CLA3 alloy steel castings. The end bracket components for rail stretcher bars were manufactured in volumes up to 200 per month with four parts set up on three different Haas machining centres.

Presenting the 50mm diameter WIDIA VXF09 high-feed milling system with five inserts in a ‘like for like’ trial, the WIDIA cutter managed to process 11 sets of four parts (44 parts in total). The ability to machine 44 parts with a single edge of the 4-sided insert was a vast improvement upon the 28 parts the previous supplier could achieve between insert failure – there was also a cost reduction in insert costs.

Moving on up 

In September, Howells Railway informed ITC that they were moving the same parts and set-up from three BT40 taper 3-axis Haas machines to one larger Haas VF11 BT50 taper machine with a 3m bed. 

"The end brackets were being produced in batches of four on three different machining centres. Each machine was dedicated to each of the three different operations," explained Howells Railway Machine Shop manager, Justin Johnson. "This was tying up three machines and two machinists, so we moved everything to the larger Haas VF11. This enabled us to set up 12 parts on the machine bed simultaneously and machine each of the three operations in one hit."

This transition to a more robust BT50 taper machine provided Murrey with the opportunity to re-assess each of the three operations from a tooling perspective. One of the first changes was the introduction of the WIDIA M8065HD face mill for removing excess stock from the castings. With a more robust set-up, ITC supplied a 63mm diameter cutter to remove 6mm of stock in a single pass from the facing and shoulder process. With the previous high feed face mill removing material at a rate of 1mm per pass, the M8065HD significantly improved the cycle time on the parts and provided a more stable process.

Building on success 

Always looking to take productivity gains to the next level, Murrey introduced the benefits of the BIG KAISER system to the end bracket components. The end brackets also require an 88.1mm bore at a depth of 65mm as part of operation 1. Prior to the process review by the ITC team, the bore was processed with a high-feed 50mm diameter indexable shell mill helical interpolating inside the bore - a process that took 3 minutes 30 seconds. 

"After looking at the options available, we highlighted the BIG KAISER boring system and discussed changing the process from helical interpolation to a plunging application. The BIG KAISER Twin Bore tooling system (SW Rough Boring Head) was selected by my colleague Simon Yeomans, our resident BIG KAISER expert," said Murrey. 

"We run the Twin Bore head at 542rpm and 81mm/min feed rate. It worked extremely well, left a fantastic surface finish in the bore and it reduced the whole cycle time by 11 mins 20 seconds or 2 minutes 50 seconds per part”.
 
Improving surface finishes 

Alluding to the benefits of this first BIG KAISER tool, Johnson continues: "By changing to the BIG KAISER system on the bore, we found a less aggressive method that improved surface finishes and reduced the stress on our machine. However, the major benefits were the cycle time reduction of almost 12 minutes for each batch of 12 parts and the tooling cost saving. We were using a high feed shell mill with 5 inserts that needed an edge change every 20 parts.

"In comparison, the BIG KAISER boring tool only has two inserts, and they only need to be changed after machining 100 parts. Not only has this made a huge tooling cost reduction, but we now only need to change the inserts once every shift as opposed to 3 to 4 times a shift with the high feed shell mill."

Adding his thoughts, Alex Barnes, the CNC programmer at Howells Railway who was instrumental in the process changes says: "As a team, we worked closely with ITC to move the components to the larger Haas VF11, which has revolutionised the process. Working with ITC, we instigated new tooling concepts and re-programmed the parts to significantly improve cycle times and increase throughput."

The diversity of the BIG KAISER range also enabled the ITC team to investigate potential improvements on the third operation of the end bracket parts at Howells Railway. Within the 12 cast parts simultaneously set up on the Haas VF11, there are 4 components set vertically, which use a 16-insert porcupine cutter to interpolate around a 44.9mm diameter spigot. At its biggest diameter, the process removes 7.5mm of stock to a depth of 40mm.
 
Reducing cycle times

Using the previous porcupine tool, the 4 spigots were machined in a cycle time of 6 minutes with significant noise and vibration throughout the process. Switching to the BIG KAISER SW twin-head overturning tool, the ITC engineers ran the new tool with just two inserts and cutting data of 800rpm and 290mm/min feed. The result was a cycle time reduction of 5 minutes 10 seconds, slashing the cycle time to just 50 seconds for four parts.

The process took 10 seconds to machine each spigot with 10 seconds traversing between the components. At the widest point of the forging, the tool is removing 7.5mm of stock material in a single pass, improving surface finishes, and tool life performance and also reducing chatter and vibration to minimise spindle load.

"It's too early to calculate the reduction in tooling costs by transitioning to the VF11 and applying the BIG KAISER tools, but we know it is significant," Johnson stated. "As an overall process, bringing all three operations to a single machine has yielded time, labour and capacity savings. What we didn’t envisage by undertaking this process is the potential benefits of changing from a BT40 machine to a BT50 from a tooling perspective. 

"The increased machine stability has allowed us to completely change the process. As a top-line figure, we know we have decreased our cycle time for 12 parts from 1 hour 38 minutes to 50 minutes. Machining over 200 parts a week on an ongoing basis, is a huge saving to our business," he concluded. 

For more information: 

www.itc-ltd.co.uk

Tel: 01827 304500