Fixed arm Carousel rotational molding machines are some of the most used machines in the industry. They are developed for high production runs of medium sized parts; Roto Dynamics as well as various other rotational molding companies use a 3 arm fixed carousel machine. Each arm is 120 degrees away from the other and is driven by a central turret. All three arms rotate in the machine as they are fixed to the turret; one arm is in the heating station the other in the cooling station and third arm is at the loading/unloading station shown here (Reference: Wikipedia):
Being able to run various molds of different sizes and material requirements is a major process advantage of the fixed arm carousel machine. Not only can different materials be run on each machine, but molds can easily be changed without having any impact on production times. However, that being said the effect of using different molds and materials creates the need for various optimum cooling, heating and servicing settings therefore dictating the cycle times by the slowest arm. This problem has been overcome by the development of the independent arm carousel machine. Independent arm machine: Independent arm machines solve the problem that fixed arm carousel machines possess; the cycle time is no longer dictated by the arm. These machines have 5 stations and have the ability to run 2-4 arms running independently of one another. The benefits provided by the independent arms include the capability to designate the vacant station as an auxiliary oven, station cooling station or additional loading station. This machine can especially be advantageous to the custom molder who is running a variety of materials and molds of different complexities.