Simple Solutions That Work! Issue 11

STANDARD MOLDING MACHINE SOLUTIONS Standard Jolt Squeeze Machines To minimize the initial green sand investment, standard molding machines offer a major advantage because a foundry can mechanize for green sand molding with reasonable initial expense, and the balance of the mold handing can be built over time. These machines can be the small 212/214 jolt machines, up through the 722 & 730 jolt mold- ing machines. These machines can use almost any standard green sand match plate and cope and drag pattern equipment. A number of flask sizes can be can be employed on the same ma- chine, giving flexibility of produc- tion and product range. A standard molding match plate solution can be found where cope and drag are formed simul- taneously. The overall operating efficiency of these machines is very much dependent on the op- erator’s ability to continually carry out these machines man- ual functions. By implementing mechanized mold handling systems, as previously stated, the machines can provide more productivity. Automatic Horizontal Flaskless Moulding (Matchplate) After the development of the jolt, rap, and squeeze mold- ing technology, the focus of the machinery for green sand mold production was put into handling systems designed to reduce the reliance on labor to achieve a more reasonable pro- duction rate. Automatic horizon- tal flaskless molding machines, sometimes known as automatic matchplate molding machines, were designed and first intro- duced to foundries in the USA in the mid 1960’s. These machines have probably had a more rapid growth in their use than any oth- er innovation to green sand mold production in the last 60 years. The main reason for this con- tinued success in the US is that many small to medium found- ries were of the type known as “Squeezer Shops”, using stan- dard jolt squeeze machines or Roto-lifts with snap flasks and matchplate. With so many matchplate patterns available from the OEM manufactur- 32 ers, it was quite common for the foundries to install one of these machines and use their customer’s existing patterns. These automatic horizontal match plate machines are a relatively economic form of molding mech- anization. The machine produces a complete mould in one cycle and only requires one machine operator who can set cores as necessary, thus removing some of the reliance on manual labor to make the mold. Production rates can be over 200 molds per hour un-cored. If cored work is required, the foundry is limited to automatic core setting if it wishes to maintain maximum production, although automatic core setting is really a misnomer, since a man is required to put the core or cores into the setting unit. Two methods of filling are used in flaskless molding: 1. Gravity fill & Squeeze 2. Blow fill & Squeeze The molding process for both the Gravity and Blow machines is virtually identical. Consequently, for the purpose of this comparison our comments will apply equally to both machines. With blow machine, the pattern plate is trapped in between the cope and drag flasks which are then tipped up on edge so that the pattern is vertical. Sand is then blown straight down from a pair of blow slots to fill the flasks from above. This means that sand, which is traveling at a very high velocity, must make a right angle change of direction in order to fill deeper green sand pockets or mold cavities. Consequently, there are frequently problems filling and drawing deeper green sand pockets and cavities. Gravity fill & squeeze machines have shown to give more consistent mold quality