Feeder Setup Research Articles

Effect of batch-to-batch variation of spray dried lactose on the performance of feeders

With the emergence of quality by design (QbD), it becomes imperative to gain understanding of the impact of batch-to-batch variability of raw materials on the performance of processes. Feeding is the first unit of operation in a continuous manufacturing line and is critical for the final product quality. The performance of feeders defines the content of components that are fed into the system and therefore the composition that ends up in the formulation. In this paper, it is investigated how and to what extent variability of lactose can impact the feeding performance in different feeder set-ups. Spray dried lactose SuperTab 11SD was selected as a material, as it is one of the most widely used filler-binders for direct compression of tablets and can make up to 70% of the tablet content. For the first time, over 200 batches were evaluated regarding the impact of batch-to-batch variability upon feeding performance in volumetric mode. Results show that for an optimized feeder set-up with 22 mm double concave screws rotating at 342 rpm, the batch-to-batch variation was negligible compared to the natural feeding variability. However, for a stretched feeder set-up with 11 mm double concave screws rotating at 514 rpm, variability in material properties introduces additional variation in the obtained feed factor. Excipient variability and feeding set-up are therefore two factors to be considered when optimizing feeding consistency. • Impact of variability upon feeding performance was investigated for >200 batches. • The batch-to-batch variability is neglectable for an optimized feeder set-up. • Batch-to-batch variability can introduce variability in a stretched feeder set-up.

Understanding the cold spray deposition efficiencies of 316L/Fe mixed powders by performing splat tests onto as-polished coatings

Some of the current trends in cold spray include the production of metal-metal composite coatings; however, the deposition mechanisms of mixed powders are often vaguely understood. In this study, single component 316L stainless steel and Fe coatings, as well as composite 316L/Fe coatings, were deposited through cold spray and the deposition efficiencies (DE) were measured. The composite coatings featuring various feedstock fractions were produced using a dual powder feeder setup. Splat tests were then performed on the as-polished coatings to investigate the deposition behavior of each component powder on the previously deposited layers. Bond ratio (BR) was determined from the splat tests to correlate with DE. Results show that the 316L powder has a better DE than Fe; whereas the DE of 316L/Fe mixed powder increases with increasing the mixture feedstock Fe fraction. The BR was found to correlate well with the DE of both single component and mixed powders. For the individual deposition behavior of the component powder, the BR of 316L monotonically decreases on the composite coating with an increasing Fe fraction; while the BR of Fe plateaus at a relatively high value regardless of the composite coating composition, which results in the overall increase of mixture DE.

Study of interaction of entrained coal dust particles in lean methane–air premixed flames

This study investigates the interaction of micron-sized coal particles entrained into lean methane–air premixed flames. In a typical axisymmetric burner, coal particles are made to naturally entrain into a stream of the premixed reactants using an orifice plate and a conical feeder setup. Pittsburgh seam coal dust, with particle sizes in the ranges of 0–25μm, 53–63μm, and 75–90μm, is used. The effects of different coal dust concentrations (10–300g/m3) entrained into the mixture of methane–air at three lean equivalence ratios, ϕ, of 0.75, 0.80 and 0.85, on the laminar burning velocity are studied experimentally. The laminar burning velocity of the coal dust–methane–air mixture is determined by taking high quality shadowgraph images of the resulting flames and processing them using the cone-angle method. The results show that the laminar burning velocity reduces with the addition of coal dust having particle sizes in the ranges of 53–63μm and 75–90μm, irrespective of the equivalence ratio values. However, burning velocity promotion is observed for one case with particle size in the range of 0–25μm at an equivalence ratio of 0.75. Two competing effects are considered to explain these trends. The first effect is due to volatile release, which increases the overall equivalence ratio and thus, the flame temperature and burning velocity. The second is the heat sink effect that the coal particles take up to release the volatiles. This process reduces the flame temperature and accordingly the burning velocity also. A mathematical model is developed considering these effects and it is seen to successfully predict the change of laminar burning velocity for various cases with different dust concentrations and equivalence ratios of the gas mixture. Furthermore, the implication of this study to coal mine safety is discussed.

The optimisation of the single surface mount device placement machine in printed circuit board assembly: a survey

This article surveys research on the single surface mount device (SMD) placement machine optimisation problem. We classify the optimisation problem into five sub-problems: feeder setup, component placement sequencing, nozzle optimisation, component retrieval plan and motion control; and analyse issues relevant to each of these. One of the aims of this article is to provide guidance to other researchers and gain a deeper understanding of the various optimisation issues that arise in this domain. This could lead to the design of improved heuristics, which are more appropriate to the real-world scheduling problem of the SMD placement machine.

Short communication: Milk meal pattern of dairy calves is affected by computer-controlled milk feeder set-up

Ninety-six calves housed in groups of 8 were fed either a high milk allowance (heavy breeds 9.6 L/d; Jerseys 7.2 L/d) or a low milk allowance (heavy breeds 4.8 L/d; Jerseys 3.6 L/d) via a computer-controlled milk feeder. Half of the calves on each allowance could ingest the milk in 2 or more daily milk portions, whereas the other half could ingest the milk in 4 or more daily portions. Data were collected during 3 successive 14-d periods, the first period starting the day after introduction to the feeder at minimum 12 d of age. High-fed calves ingested their milk in 4.0 and 4.9 meals for a minimum of 2 and 4 portions, respectively, whereas low-fed calves ingested their milk in 2.4 and 4.4 meals for a minimum of 2 and 4 portions, respectively. Calves on a high milk allowance had fewer milk meals over time, whereas calves on a low milk allowance had the same number of milk meals throughout. Thus, the development from small and frequent milk meals to fewer and larger meals reported by studies of natural suckling was also found among high-fed calves on a computer-controlled milk feeder. Irrespectively of minimum number of milk portions, the low-fed calves had more unrewarded visits to the computer-controlled milk feeder, indicating that they were attempting to get more milk. The results of the present study suggest that offering a high milk allowance and avoiding restriction on meal pattern may result in a feeder use that more closely resembles natural suckling.

ガントリ型チップマウンタ向け外段取計画アルゴリズム(<小特集>生産加工・工作機械の規範2008)

ガントリ型チップマウンタ向け外段取計画アルゴリズム(<小特集>生産加工・工作機械の規範2008)

A memetic algorithm-based heuristic for a scheduling problem in printed circuit board assembly

This research develops a memetic algorithm to solve Printed Circuit Board (PCB) scheduling with sequence-dependent setup times on a single machine with constrained feeder capacity. The objective of the scheduling problem is to minimize the total weighted tardiness. A memetic algorithm-based heuristics is developed by integrating a genetic algorithm, Minimum Slack Time (MST) scheduling rule, “Keep Tool Needed Soonest” (KTNS) policy, and a local search procedure. Application of the MA results in two outcome plans: a scheduling plan and a feeder setup plan. Numerical experiments show that compared to a number of commonly used dispatching rules, the memetic algorithm provides better solutions in term of minimum total weighted tardiness. Even the computation is the highest, it still practical. Calibration of MA parameter values is also explored in this study.

3505 多品種プリント基板実装ラインにおける段取計画技術(S50 生産システムの新展開(基礎理論/産業応用),21世紀地球環境革命の機械工学:人・マイクロナノ・エネルギー・環境)

This paper considers the operation of an electronic component placement machine. We developed a new feeder setup planning algorithm for a turret-type placement machine to increase productivity of printed circuit board (PCB) assembly. It is based on offline setup strategy which exploits a feeder hot-swapping mechanism of the placement machine. The proposed algorithm is examined by real-life PCB data. The productivity by the offline setup strategy is compared to those of unique setup and group setup strategy. It is shown that our algorithm achieves significant improvement in productivity.

C31 ガントリ型チップマウンタ向け外段取計画アルゴリズム(OS-4 生産システムとCAD/CAM(2))

C31 ガントリ型チップマウンタ向け外段取計画アルゴリズム(OS-4 生産システムとCAD/CAM(2))

A triple objective function with a Chebychev dynamic pick-and-place point specification approach to optimise the surface mount placement machine

Optimisation can play a major role in improving the throughput of surface mount placement machines. Most previous work has reported on improving only the assembly cycle time. The movement of the feeder carrier and PCB table are not always factors which are minimised. In this paper we introduce a triple objective function with a Chebychev dynamic pick-and-place approach to optimise the sequential pick and place machine. We are focusing on improving the feeder setup. The aims are to minimise the robot assembly time, the feeder movements and the PCB table movements. To provide flexibility to our approach, we integrate three weighted parameters into the triple objective function such that one can vary the importance of each factor to be minimised. Experimental results show that our approach gives good robot assembly time and less movement of the feeder carrier and PCB table.

COMPONENT TO MULTI-TRACK FEEDER ASSIGNMENT AND BOARD SEQUENCING IN PRINTED CIRCUIT BOARD ASSEMBLY

Proper planning of multi-track feeders in the printed circuit board (PCB) assembly can increase the capacity of surface mount machines and reduce feeder changeovers. This paper describes a methodology for developing a process plan to minimize the feeder setups in multi-track feeder systems. Two problems are investigated: component to multi-track feeder assignment and PCB sequencing. The assignment problem is formulated as a multi-dimension symmetric assignment problem with an integer-programming model. The objective is to maximize the total similarity of the component assignment. The PCB sequencing problem is solved in three stages: component and PCB grouping, intra- and inter-group PCB sequencing, and feeder setup planning. The interrelationship between the assignment and the sequencing problems is also investigated.

Planning of Component Placement/Insertion Sequence and Feeder Setup in PCB Assembly Using Genetic Algorithm

A new application of the genetic algorithm approach is introduced to solve printed circuit board assembly planning problems. The developed genetic algorithm finds the sequence of component placement/insertion and the arrangement of feeders simultaneously, for achieving the shortest assembly time, for three main types of assembly machines. The algorithm uses links (parents) to represent possible solutions and it applies genetic operators to generate new links (offspring) in an iterative procedure to obtain nearly optimal solutions. Examples are provided to illustrate solutions generated by the algorithm.