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PRODUCTS SIGMA

PRODUCTS

PRODUCTS

SIGMA

High performance industrial gypsum

sigma

It is extra precision and high strength gypsum used for precision mold, inspection, copying and industrial purpose. It is mainly used for making and copying model, test models for mold making, replacement for wooden pattern metal plastic pattern and other cases for making plaster molds which demand intensity, hardness, measuring precision. Extra Hard Case Mold l For Extra Precision Mold Producing l For Molding Shrink rate Correction I For Non Ferrous Metal Casting

Main Use
For plaster mold manufacture and copy, for test models for mold making, for replacement for wooden, metal, resin, molds for plaster molds which demand intensity, hardness, measuring precision, for plaster case for gypsum mold making
  • Gemstone Series
    Product Number Gemstone N-2000 Gemstone N-1000
    Characteristic/Purpose Large Sized Precision Modeling
    Low expansion, High Strength, High Surface Strength     		Small Sized Precision Modeling
    High Strength, Low Expansion, High Surface Strength
    Standard Mixing ratio(%) 28 28
    Beg Influx(min) 15 13
    Start Setting(min) 25 18
    Termination(min) 60 50
    Expansion At Termination(min) 0.15 0.15
    Compressive Strength Wet(kgㆍf/㎠) - -
    Dry(kgㆍf/㎠) 700 600
  • L-Series
    • Category is a representative plaster with high degree of hardness and intensity that is most widely used in plasters for a low-expansion model.
    • L-Category for the number, type and item of its products are set up, you can select what you want depending on your need and you can make models with high degree of precision economically.
    Types, characteristics and purpose of L Series
    Product Number L-13 L-11
    Characteristic/Purpose This is the most commonly used plaster breed and is used for molds and also lamination. Hardening Time is long, there is very little expansion and thus is commonly used for molds with larger models.
    Standard Mixing ratio(%) 42 43
    Beg Influx(min) 5-15 5-10
    Start Setting(min) 15 30
    Termination(min) 90 120
    Expansion At Termination(min) 0.015 0.015
    Compressive Strength Wet(kgㆍf/㎠) 130 110
    Dry(kgㆍf/㎠) 300 280
    General Features of L-13

    The plaster slurry of L-13 is put inside by increasing its viscosity as time passes (liquidity decreased) > coagulation > It is coagulated in order of hardness and begins to expand and generate heat following the order.

    • When the temperature of the generated heat reaches the peak (completion of coagulation), the expansion reaches its peas as well, resulting in the lowering temperature and decreasing expansion. Its wet hardness becomes the highest after 2 hours of the completion of coagulation.
    • The physical features of plaster such as the duration of hardness and expansion are affected by various factors such as the temperature of atmosphere, temperature of water, proportion of water, mixing speed, mixing time, and the size of forms made. Therefore, in order to make an accurate model, keep all these factors consistent.
    How to Use L-13
    • How to Use L-13
    • Pre-process of Model: When a model is porous (wooden pattern, plaster), process it with a high-quality and clean paint.
    • Separating: The separating agent of MUNGYO Gypsum is recommended
    • Slurry Processing: Prepare water in an appropriate amount. Apply plaster into the water. When the plaster is blended with water, stir it for 3~8 minutes.
    • Formation: Put the mold immediately into it. Wait until the lamination gets more viscose and work with it.
    • Molding: Make sure to inject instantly when molding. At the time of lamination, make sure to start working after leaving for a long time until viscosity increases.
    • Dry: If drying is required, hot wind circulating dryer of 45~55℃ is recommended. However
    • when cooling it, do it in the air cooler.
  • OMEGA Series
    • By using Ω-category plaster, you do not have to make an extended wooden pattern in extra.
    • Ω-category plaster is essential in extending a mold
    Ω – Type, Quality and Use of System
    Product Number Ω - 8 Ω - 10 Ω - 12 Ω - 20
    Characteristic/Purpose Ideal for correcting the contraction of a resin mold Representative for correcting a zinc mold Ideal for correcting the contraction rate of zinc, aluminum, and light synthetic metallic molds Ideal for correcting the contraction rate of general metallic molds
    Standard Mixing ratio(%) 35 35 35 35
    Beg Influx(min) 8 8 8 8
    Start Setting(min) 15 15 15 15
    Termination(min) 60 60 70 80
    Expansion At Termination(min) 0.80 1.00 1.20 2.00
    Compressive Strength Wet(kgㆍf/㎠) 190 180 160 200
    Dry(kgㆍf/㎠) 270 260 240 200
    How to Use Ω Category Plasters and the Features of Ω Plasters

    Plasters belonging to Ω category have big cooling expansion (0.5~2.0%) which cannot be seen in the existing burnt plaster by processing the burnt plaster with high intensity in a special way. They are used for making expansion models expansion molds which are to correct the solidifying contraction of metals or synthetic resins. The expansion size of Ω plasters varies according to the shape and material of a model, size of a model and water temperature and atmospheric temperature depending on seasons, it is recommended to order and production after consultation.

    How to Use
    Cautions when stirring
    01 Measure the amount of plaster and water accurately. (Follow the proportion as designated.)
    02 When applying plaster, do stir altogether.
    03 Container for stir: Do not use an alkali container. Use 1 or 2 containers fit for the amount of plaster used so that slurry can be formulated in each container if possible
    04 Stirrer: Since the apparent specific gravity of plaster is low, in order to get uniform slurry in a short time, use a stirring wing (cautions for the size and shape) fit for a stirring container with high efficiency.
    05 Stirring time
    • The time used for applying plaster should be as short as possible (within 5 minutes).
    • And the time taken for stirring should be 7~8 minutes.
    • Here, the time used for completing applying plaster is counted for the time for stirring.
    • To be specific, if you use 4 minutes in completing the application of plaster, you can put by stirring it for 5~6 minutes from the completion.
    The time for hardening and rate of expansion vary according to the condition for plaster stirring such as the amount of plaster used, size of a container, size of a stirring wing and shape and efficiency.
    Stirring Time Stirring Efficiency Hardening Time Expansion Rate
    Shorter Longer Lower
    Shorter Quicker Higher
    Lower Quicker Higher
    Higher Longer Lower
    06 In case when stirring containers are plural, make sure that uniform slurry is formulated in the frame.
    07 When the model is complicated in its shape, especially a concave one, apply low plaster L-13 to a convex cast first and then use it. Also, if there is an obviously sunken spot on it, use it as a separate cast. It is because that approximately 45% has already been expanded especially when releasing.
  • Product Number C-2
    Characteristic/Purpose Tire mold, light alloy mold, good lnbrication of casting and size
    Percentage of Water(%) 45-47
    Pattern Extraction Time(min) 50-60
    Expansion At Termination MAX(%) 0.25
    Water Strength Tensile strength(kgㆍf/㎠) 10
    Compression(kgㆍf/㎠) 30