Rupert Hanak, head of production engineering at Martin-Baker, explains the difficulties the company needed to overcome for efficient production: “We have thousands of different components and batch sizes are often 5 to 15 parts. The length of each production run is too short for us to develop faster cycle times, so the key objectives are an extremely quick change over time between different parts, and process reliability so that we know that parts will be right first time.”

At the heart of Martin-Baker’s production is a manufacturing cell consisting of four DMG MORI NHX4000 2^nd Generation horizontal machining centres, each with 240 tools, connected with a DMG MORI LPP (Linear Pallet Pool). This system has 70 pallets and supports 500 different active parts. A VIO tool presetter services the machines and links them, to download the tool setting data. Martin-Baker has a core of about 200 standard tools, which the CNC programmers have to work within, on each of the NHX4000 2^nd Generation machines.

The production schedule is controlled from Martin-Baker’s SAP system, which displays the next four week’s worth of jobs on a terminal on the LPP. Engineers select the order in which they should be run, picking long running safe parts for the unmanned night shift and more challenging work for day shifts.

Data driven

Hanak adds, “We use Mori Messenger to monitor machine activity and gather metrics. The system shows the run rate of the machines and displays alarms. I can drill down into the data to find the problem, which could just be machine loading and work availability or tooling problems. Essentially, all our decisions are data driven.”

Within the software solution, SAP knows the workholding requirements of each job, the machining time and the tooling. Linked to the LPP system the correct pallet and fixture is presented to the engineer for loading. Extra software supplied by DMG MORI detects broken tools and tool ‘out of life’ situations, ensuring that a job which requires the faulty tool is not loaded to the machine and automatically cutting another job from the work list, while the problem is remedied. 

The system can recognise sub locations on a pallet. DMG MORI has added extra buttons on the control system which make it possible to skip these sub locations if no material has been loaded. Hanak says: “We have had a lot of applications support from DMG MORI to tailor the systems to our requirements. A DMG MORI engineer is on site permanently to ensure the smooth running of our machines and to maintain them. We apply SMED (Single-Minute Exchange of Dies) principles to all machines, and DMG MORI has been a very good partner in helping us get to the level we have achieved.”

The NMV3000 DCG 32 pallet machines enable multiple operations to be combined on one machine using their 5-axis capabilities. One machine is used to produce a rocket motor end cap family of parts, running one manned shift and 16h unmanned, yet still achieving 80% OEE. Hanak adds, “With 5-axis and turning capability on one machine we can go from raw material to finished part in one step. We used to subcontract some of the parts but, by making them in-house, we now have more control over security of supply. Additionally, completing each job on one machine eliminates the chances of something going wrong associated with multiple operations.”

Martin-Baker has a range of NTX, NT and NL turning centres. Rationalisation of bar sizes minimises changeover times between parts and, when the bar needs changing, this is achieved within 15min. A CAPTO interface on tools and a tool management system eliminates wasted time for sister tooling replacement and reloading of offsets. DMG MORI has added special part conveyers to safely unload critical components which cannot have any surface imperfections. One of the NL machines is even used for machining rocket fuel and has been heavily modified to provide fire damping and remote operation from a safe room.