Matchplate Conversion System

General

Through the years, more and more foundries have converted from greensand matchplate molding to no-bake. Often, the conversion of tooling has been of exorbitant cost or the cost of inefficiency due to lack of conversion has resulted in the same, high long-term cost.

For these reasons, Palmer has developed a line of basic matchplate conversion systems designed with simplicity, low tooling cost, and high efficiency in mind. The concept is to convert a green sand tool to the no-bake process with minimal rigging costs while maintaining high productivity.

Systems range from a simple single molding station to a multi-station carousel operation. Based around the inherent efficiency of no-bake molding, the systems are easily expandable to virtually any conversion application.

One of the greatest problems in converting to no-bake is the handling of molds. Flaskless molding is the method of choice. Conversion of a pattern to flaskless molding involves simply building a durable wooden or metal frame on each side of the pattern to replace either tight or snap flasks and attaching either a fixed or removable trunion to each end of the plate.

This low cost conversion eliminates the need to schedule around flask and mold jackets. The frame created should be sufficiently well built to stand up to rapping from mallets and should contain sufficient draft to allow the mold to draw easily after cure.

As far as the equipment goes, Palmer has done everything possible to minimize components and controls and keep the systems as simple as possible.

Benefits

• Low green sand to no-bake tooling conversion cost
• Highly efficient molding operation
• Virtually no lifting by the machine operator
• Less operator training

Matchplate Conversion System – Single Station

Similar to "Roto-Lift" methods, the MCS-1 features dual lifting arms that are used to lift a matchplate set for stripping and rolling. This system most closely resembles a typical single pattern jolt squeeze type green sand molding station and would be the easiest for a squeezer molder to learn.

• Place the matchplate set with frames into the device. The lifting arms mount semi-rigidly to trunions located on the original matchplate. 
• With the drag facing up, mold and compact the drag as necessary. Note: Sand is produced by an appropriately sized continuous mixer. 
• Allow the drag to cure. 
• Once cured, activate the lifting arms and roll the mold so that the drag is in the stripping position.. 
• Lower the matchplate set down to the conveyor. 
• Actuate the stripping cylinders to slightly raise the mold box off of the conveyor. 
• Rap the drag and draw. Once the drag releases from the box, lift the arms and push the mold off to the closing station. 
• Lower the mold box. 
• Fill the cope, compact, and strike off. Repeat the above procedure for the cope. 
• Repeat.

Please note that this design, while simple, is not the most efficient as the operator must wait for the sand to cure. For this reason, we recommend the following.

Matchplate Conversion System – Dual Station

The dual station MCS retains the simplicity of the single station yet is capable of producing double the mold quantity in the same allotted time. The concept is to have a swiveling mixer between two molding stations. Each molding station has its own discharge conveyor. The molding process is:

• Fill drag #1. 
• Swing mixer to #2. 
• Fill drag #2 while #1 is curing. 
• Roll and strip drag #1. 
• Swing mixer to #1. 
• Fill cope #1. 
• Roll and strip drag #2. 
• Fill cope #2 
• Roll and strip cope #1. 
• The process continues as above.

This method is ideal for motivated molders that have a good sense of timing based on traditional greensand operations.

It is important to note in this design that the mixer should be sufficiently sized such that the speed of the mixer’s fill time does not affect the overall process time. System speed should be dictated by resin system cure time.

Matchplate Conversion System – Four (Or More) Station Carousel

The MCS-4 is a slightly more advanced molding system designed to run four or more matchplate sets at a time. It is based on the carousel molding principle where the machine does the material handling and the operators are stationary.

There are two primary operators for this system, one for molding and one for stripping. The basic order of operations is:

• Molder fills first drag and indexes the carousel 90 degrees. 
• Molder fills second drag and indexes. 
• Molder fills third drag and indexes. At the same time, the secondary individual strips the first drag. To strip the mold, the operator inverts the matchplate set on the plate trunions and locks it into position. A hydraulically actuated scissor lift table is raised to just below the mold box. The pattern is rapped and the mold falls out onto the scissor lift table. The table is lowered and the drag is pushed onto the holding conveyor located on the carousel. The mold is left in the inverted position (cope up) for filling. 
• Molder fill fourth drag. Helper strips second drag. 
• Molder fill first cope. Helper strips third drag. 
• This process continues as required. 
• When the first cope and drag set are stripped, they are pulled out together and sent to the mold prep and closing area, this frees the hold zone for the next drag of this pattern.

It is important to note in this design that the mixer should be sufficiently sized such that the speed of the mixer’s fill time does not affect the overall process time. System speed should be dictated by resin system cure time.

There are several process items that need to be addressed by the particular foundry in question when considering this type of system. The basis of the system is constant strip time. Jobs that run together on the carousel should have the same strip times to allow for the smoothest operation. In some instances, mold pins will be required when the molds are inverted to prevent the molds from falling out. Generally, a simple pin / holes method works. Two pins are sufficient to retain the mold.

There are many options that can be installed on system of this sort and they are highly installation dependant. For assistance in specifying the MCS-4, please feel free to contact out offices.