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Solution Driven Machining

Engineering Elbow Bend - Cast Fittings

One of the main competitive advantages of Mann Engineering Ltd is that throughout our staff, we possess a wide array and decades of precision machining know-how and this knowledge was used to the full in solving an issue for a fluid dynamics customer in the UK, that they had been experiencing issues with previous suppliers, in relation to swarf and metal particles in 90 degree and 45 degree cast forgings, where these metal particles had the potential to affect the integrity of the pump on full assembly of their product.

We took on the challenge to firstly produce a totally clean machined elbow and secondly to reduce the manufacturing cost of the suite of fittings for this customer. We carried out an A4 on the initial batch of sample parts we manufactured. Normally these type of parts would be cleaned out manually with a file or a wire attachment. By dissecting the part, we ascertained that the main issue of the particles was caused by the intersection of where the drills would have met at the internal radius, which left a small burr at a point that was both hard to see visually and to get to and it was this burr that could eventually break off, when pressurised fluid was pushed through the elbow.

As a team we discussed various ways of eliminating the issue, discussed and investigated at the time were solutions such as tumbling in one of our Vibra bowls using different types of abrasive media and we also sought advice on high-tech solutions such as Thermal Deburring. We used contacts in our industry network and after debating the issue with some of our machining colleagues in the United States, we sourced a cleaning attachment with a flexible head, that was at patent stage, that could be added to the twin turret lathe set-up, that was able to smooth the step and clean the inside bore while still in process on the machine. Parts were finally cleaned on our Ultrasonic machine and a quick visual check was carried out using a micro camera with a light, that was inserted into the fitting, just to ensure that no swarf or scoring existed that could cause an issue later on. Problem solved.

In the photo, you can see on the left the forged blank in its raw state, the photo on the right is the blank after machining. Unlike the majority of our work which is bar fed, these parts are what is called Billet work, which means they are manually loaded and unloaded individually. Key to reducing costs was to reduce set-up, changeover and handling. To achieve this we first of all upgraded our design software to allow us to design, draw and manufacture our own range of jaws for each type of item, as against buying jaws off the shelf. It also meant that we could make jaws in two to three hours internally, instead of waiting two to three days.

We then built jigs around manufacturing two parts within the machine at the same time, the left hand jig being drilled and turned by the first spindle and the part in the right hand jig being finished drilled and turned by the second spindle. This process was carried out on one our our twin spindle, triple turret Citizen Miyano Lathes (ABX64) We also rotated one of our machines so as the loading doors were facing each other, so as now we had scope for one operator to load and unload two machines in tandem. With these implementations we were able to give our customer an overall cost saving of 8%. Our current investigation on how we can speed up this production process and make further cost reductions, is with the use of programmed robotic arms to load and unload, as ever Mann Engineering strives to embrace new technologies and improve our service offering to our customers.