【正文】 ) (development 1) (development 2) (production)Figure Development RogueBefore developing a part with those tight tolerances, the technology of high precision injection moulding had to be proved. For those purpose a test part was defined (feasibility part and tool). The first step made in designing the function of the Rogue was to find a solution for accurate guidance to assure the position of the carriage in relation to the shaft. By creating two small guiding surfaces on the bearing surface the required quality of highaccurate surfaces in each plastic bearing reduces. The shape of the bearing is called veebearing (two linecontacts, see figure ) and one of the goals of the carriage motion design is to assure that the carriage never leaves its bearing surfaces. The solution is to design the carriage centreofgravity and rod attach point as close together as possible. The costs for the guidance could be reduced with this solution.To position the cartridges very accurately in the slots, six degrees of freedom of the cartridge have to be fixed. By creating six trimsurfaces in each slot, which can be very precisely manufactured in the mould, it is possible to tweak these surfaces. With this solution it is possible to adjust the inserts of the mould that the parts can be produced within the tight tolerances.In this chapter the development of the Rogue will be discussed by four aspects influencing high precision injection moulding: product design (), mould design (), material () and process design (). First the required tolerances will be discussed. Tolerance analysisA tolerance analysis has been made to get more information about the relation between the required tolerances and the feasibility of the product in plastic. The most important dimensions are related to the guidance of the carriage and to the position of the cartridges in the slots.Important dimensions are processed into the graphic below (see appendix C2 for the dimensions).This graph is based on a material choice from group A (materials with low shrinkage, thus the potential to be accurate). With help of the booklet “Attainable tolerances” it is possible to define the class of mould to attain the required product tolerance. This graph shows worst case, where the dimensions are not tool bounded. Some of the dimensions are not feasible in plastic as long as these dimensions are not toolbounded. To make the tolerances technical feasible it is possible to choose the references different, with the goal to construct the dimensions in one mould half (tool bounded). By only tolerating the functional dimensions in another way, the attainable tolerances bee higher. In reviewing a design from the customer the tolerances can be discussed to comake a feasible part (Appendix D).KN not feasible in plastic I precise class II accurate class Graph Tolerances RogueThree references A, B, C (see figure ) are used to build up the dimensions in the product. Reference A controls four degrees of freedom。 translation Y and Z and rotation around Y and Z. Reference B controls rotation around X and reference C controls translation X. HP designed six trimsurfaces per slot to achieve high precise position possibilities of the cartridges in the slots. In the Xplane three trimsurfaces X1, X2, X3 control translation X and rotation around Z and Y. In the Yplane one degree of freedom is controlled。 translation Y. In the Zplane two degrees of freedom are controlled by two trimsurfaces Z1 and Z2。 translation Z and rotation X. Figure References (A, B, C) and trimsurfaces (X1, X2, X3, Y, Z1, Z2)ConclusionsThe requirements of the positioning of the cartridges in relation to the carriage are the hardest. The positioning of the cartridges is very important。 if the cartridges are not positioned very well the printing process will reduce dramatically in quality performance. Six trimsurfaces per slot must guarantee a precise position of the cartridges. The tolerances of the trimsurfaces are tight, but are designed for tweaking.The material is polycarbonate filled with carbon, which is a material in group A with the best possibilities for precise products. The most accurate dimension is in class I (precise). The dimensions related the slots to in Xdirection are the most critical and have to be proper to the mould. The most precise dimension is 177。 20 mm and can only be realised when the dimension is tool bounded, with a precise mould, a technical optimal process, group A material and tweaking of the moulds. Product DesignThe product has been designed with accurate datum surfaces that can be tweaked during the mould optimisation. The surfaces are spreaded in three directions and three trimsurfaces are chosen on a plane in the most important direction (Xplane). With spring elements the cartridges are contacted to the six trimsurfaces. The spring fits in a thinned down section of the central walls. To make the inserts as identical as practical there is a fifth thinned down section in the fifth wall, which will not be used.The surfaces are as good as possible designed parallel to each other. In this way you avoid changing of dimensions in other directions due to tweaking. To overe possible warpage of the wall and flashes, the trimsurfaces are placed mm above the surface. In the design the point to measure defines a surface of 2 x 2 mm. The trimsurfaces in vertical direction have a diameter of millimetres. The trimsurfaces on the bottom are extended to the top to make releasing possible. Rogue is designed to minimise difference in shrinkage, because it causes warpage. Wall thickness is as constant as possible. The general wall thickness is mm and ribs and bosses are generally 80% of the wall thickness. To avoid warpage Rogue has been designed as stiff as possible on precise surfaces. Cross ribs are applied in the middle and radii are applied.The influence of sink marks is