This page contains a Flash digital edition of a book.
Production | DFM


There’s more to a successful DFM project than just ‘can the part be moulded?’ André Eichhorn looks at how good design can simplify downstream production


Design for peak production


Previous articles in this series have explored many of the key considerations that need to be taken into account during the DFM phase of a product develop- ment project, with the key focus on how to design a part in such a way that it can be injection moulded without signifi cant problems. Following those guidelines makes it possible to increase part quality and reduce produc- tion costs. However, there is another aspect of part design that it is also important to consider during the DFM process that goes beyond the question of ‘Can a component can be injection moulded?’ Anyone that has spent any time involved in active project support work will have seen many occasions where the part has been developed to be within specifi cation and to meet all visual quality and given tolerances, but simply cannot be handled through post-moulding operations such as cutting, plating, painting. It sometimes cannot even be reliably picked out of the mould tool by a robot. Oversights such as this this can end up in expensive


production equipment modifi cations or additional manual work requirements to manufacture a product. In most cases, a specifi c supplier of post processing equipment will be involved at a certain point in the design process and asked if the proposed design can be removed, handled, painted, and assembled in a cost-effective way. However, it is often the case, unfortunately, that this involvement happens when the


www.injectionworld.com


overall product design is very mature and fi rm. This article will discuss some specifi c examples where robots, plating, painting and assembly can have an impact on DFM considerations.


Thinking about automation There are a number of specifi c reasons for using a robot for part removal from the mould tool:  Avoiding damage to the part caused by dropping from the mould;


 Reducing the risk of damage to the mould by trapped components;


 Simplifying separation of component and coldrunner;  Maintaining correlation between each part and its mould cavity;


 Delivering oriented parts into assembly lines or post processing. The robot end-of-arm-tooling can include features such as grippers, vacuum cups or unscrewing units. These need to be reviewed during the DFM process to determine which specifi c system should be applied to remove the part from the mould tool most reliably. The externally-threaded component shown in Figure 1 presented a problem in that it was not acceptable to have a slider split line for the outer thread on the component surface. As a consequence, some design features on the inside of the component geometry had to be modifi ed to enable the required unscrewing unit to


November/December 2013 | INJECTION WORLD 61


Above: Good part design is the key to fast and effi cient automated production


PHOTO: STAUBLI


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68