Cycle time reducing

A high-throughput approach to HPLC-MS/MS for metabolite identify-cation was also described by Dear and co-workers [29], where up to six hydroxylated isomers were chromatographically resolved in 1 min with the overall cycle time reduced to 5 min on a monolithic column (4 mL/min). 

Such RIM IMR technology has been developed by Dow and 1s 1n the final stages of production qualification at major RIM molders. While the details of this technology are beyond the scope of this paper, the impact of an effective IMR on RIM economics can be addressed. This data 1s shown on "Table X", where one can see cycle times reduced from 120 seconds to 90 seconds the elimination of nonproductive mold cleaning time and the elimination of scrap resulting from external mold release buildup. The reduction in part cost 1s significant the unit cost for the body panel is reduced from 11.72 to 9.55 for an 18.5% production cost reduction. 

Increase productivity increase yield, reduce cycle time, reduce or consolidate unit operations, increase reactor volume efficiency... 

The industrial engineer can apply a variety of mathematical and engineering tools and techniques in the planning and management of effective transportation networks and systems in order to reduce or minimize costs, improve cycle time, reduce service failures, and so on. The industrial engineer plays a critical role in the development of efficient delivery routes, schedules, and plans and also helps in the design and implementation of transportation information systems. 

Because of the low melt viscosity of LCPs, thin sections can he molded with highly filled (70%) LCPs. The addition of hulk lubricants reduces the melt viscosity. Injection molded parts are produced with a minimum of molded-in stress, little or no flash, and high dimensional stability. Fast cycle times, reduced mold wear, elimination of secondary operations, and other processing and performance gains of LCPs often lead to lower overall finished part costs even below those of less-expensive resins. 

Wall thickness can be decreased or increased by adjusting the amount of charge and the cycle time. Reducing the heat that is supplied to certain areas of the mold reduces the thickness of the part at those points. Areas that should be thiimer can be shielded by insulation to reduce the build-up of molten resin. Conversely, extra heat is directed at the areas where more thickness is required. The distance between adjacent walls should be at least four times the wall thickness of the part to prevent bridging of the resin.1 1... 

Figure 4.15 Overlapping batches in Example 4.5 reduces the batch cycle time.

The batch cycle time has been reduced from 2.6 to 1.3 hours. This means that a greater number of batches can be processed, and hence, if there are two reactors each with the original capacity, the process capacity has increased. However, the increase in capacity has been achieved at the expense of increased capital cost for the second reactor. An economic assessment is required before we can judge whether the tradeoff is justified. 

Increasing the size of equipment in the steps which limit the batch cycle time to reduce the dead time for those steps which are not limiting. 

An important aspect of this procedure is the use of latent acid catalysts, such as phenyl hydrogen maleate, phenyl trifluoracetate, and butadiene sulfone. These catalysts reduce the peak exotherm from over 200°C to 130—160°C. The resin catalyst mixture has a working life of up to several days at RT. The elevated temperature of mol ding these latent catalysts generates the corresponding acids, namely, maleic, trifluoracetic, and phenolsulfonic, which cataly2e the resole reaction. Typically, a cycle time of 1—2 min is requited for a mold temperature of - 150° C. 

Reinforced Thermoplastic Sheet. This process uses precombined sheets of thermoplastic resin and glass fiber reinforcement, cut into blanks to fit the weight and size requirements of the part to be molded. The blanks, preheated to a specified temperature, are loaded into the metal mold and the material flows under mol ding pressure to fiU the mold. The mold is kept closed under pressure until the temperature of the part has been reduced, the resin solidified, and demolding is possible. Cycle time, as with thermosetting resins, depends on the thickness of the part and the heat distortion temperature of the resin. Mol ding pressures are similar to SMC, 10—21 MPa (1500—3000 psi), depending on the size and complexity of the part. 

The prevacuum technique, as its name implies, eliminates air by creating a vacuum. This procedure faciUtates steam penetration and permits more rapid steam penetration. Consequendy this results in shorter cycle times. Prevacuum cycles employ either a vacuum pump/steam (or air) ejector combination to reduce air residuals in the chamber or rely on the pulse-vacuum technique of alternating steam injection and evacuation until the air residuals have been removed. Pulse-vacuum techniques are generally more economical vacuum pumps or vacuum-pump—condenser combinations may be employed. The vacuum pumps used in these systems are water-seal or water-ring types, because of the problems created by mixing oil and steam. Prevacuum cycles are used for fabric loads and wrapped or unwrapped instmments (see Vacuum technology). 

Improperly set tolerances and uncontrolled variation are one of the greatest causes of defects, scrap, rework, warranty returns, increased product development cycle time, work flow disruption and the need for inspection (Gerth and Hancock, 1995). If manufacturing processes did not exhibit variation, quality problems would not arise, therefore reducing the effects of variability at the design stage, in a cost-effective way, improves product quality (Bergman, 1992 Kehoe, 1996). 

Related to competitiveness measures - improved quality, compressed lead time, reduced life-cycle costs, increased flexibility, improved productivity, more satisfied customers... 

Unlike polyurethane-RIM processes, nylon-RIM reactions are endothermic and require temperatures of 130-140°C. In contrast to the polyurethane-RIM systems, this enables thick wall parts to be made. Cycle times of 2-3 minutes are comparable to those for polyurethane-RIM. In the development stage, current work is concerned with reducing moulding times and optimising moulding conditions. 

The need to optimise conditions to allow a maximum rate of crystallisation and thus reduce cycle times. The maximum rate of crystallisation is reported to be at about 55-60°C, which, interestingly, is significantly closer to the Tg than the (see Section 3.3). 

---