Top 10 Rules to Optimize RF Heat Sealing Dies

Thermex-Thermatron has accumulated over 80 years of industrial experience as a leader and innovator in the radio frequency (RF) and microwave (MW) technology arena. On the production floor, a combination of the right equipment and the right practices will yield efficiency, accuracy, and safety. Here are 10 crucial pointers condensing a wealth of insights, teaching you how you can obtain superior results when using RF heat sealing dies. 

RULE #1: LOOK INTO CAPACITY BEFORE YOU ORDER YOUR NEXT RF HEAT SEALING DIES 

Check the RF Heat Sealing chart to determine the capacity of your RF Equipment. This will help you determine whether the size of your run justifies the cost of multiple unit RF heat sealing dies.

RULE #2: WHEN YOU NEED TO ORDER NEW RF HEAT SEALING DIES — SPECIFY THE DETAILS

There always comes a time when you must order new RF heat sealing dies. However, complications often lie in lack of attention to critical details. From awareness of equipment features to knowing what material and how much to spend to examine each step of the process accordingly, make sure to watch out for these six components. 

  • Specify the equipment brand, size and mounting hole centers, size of bed plate, and platen. Additionally, look into the need for a heated platen.
  • Identify the thickness of plastic to be used and desired trim for tear seal waste (typically ¼” to be torn away after sealing).
  • Specify any special effects.
  • Send one or more of the following: 
    • Blueprints 
    • Patterns 
    • Sewn samples
  • Send enough material for testing all phases of the project thoroughly.
  • If used, specify which types of steel and height will be required for cutting dies.
Thermex-Thermatron RF Heat Sealing Tips — Tips to Order RF Heat Sealing Dies

RULE #3: WHEN PREHEATING DIES WITH PREHEATED PLATEN, START WITH 150 ºF

Before you begin utilizing RF heat sealing dies, prepare for optimum equipment performance by preheating that morning and adapting your temperature later. Keep in mind, for appliqué sealing, a heated platen is a must.

  • For maximum efficiency of tools, at the start of each day, preheat the dies by setting the thermostat to 150 ºF.
  • Maintain this temperature until your die heats up from use, and then cut back on the thermostat.

RULE #4: UNDERSTAND WHEN AND HOW TO BEST INSTALL STOPS IN DIES

There are two cases we recommend that you absolutely need to install mechanical stops in your heat sealing dies. 

  1. When seeking a controlled penetration seal.
  2. In cases that necessitate appliqué sealing. 

Regardless of what sealing process you choose, note that all mechanical stops should be fully adjustable. 

RULE #5: CHECK THE SET-UP OF YOUR EQUIPMENT BEFORE AND AFTER USE

As celebrated photographer Sam Abell said, “It matters little how much equipment we use; it matters much that we be masters of all we do use.” Any time you’re utilizing dielectric welding equipment, thoughtful regard to how you have set up your process will be a huge determinant of seals that get overheated, whether or not your seals are strong, and your die lines even. Pay careful attention to how you mount your dies, if your dies and trays are in the right operating sequence, and when to lower production’s time or power. 

  • Before mounting the dies, be sure to check that the head of your machine is level.
  • To check equipment platen levelness: 
    • Place one (1) sheet of plain paper on the bed of the platen. 
    • Cover it with one (1) layer of carbon paper (carbon side against plain paper). 
    • Do not overlap.  
    • With the RF switch off, bring the upper platen with the die attached down on the carbon paper.
    • Release and check carbon print on the plain paper for even die lines.
  • Check to see that the dies and trays are set up in proper sequence of operation.
  • To start test sealing: 
    • Start with low RF and seal time.
    • Increase seal time first.
    • Then raise RF and adjust air pressure. Do so until you have achieved your desired sealing strength.
  • After production has been running for a time and dies are thoroughly heated to operating temperature, cut back on time or power gradually.
    • This will prevent your seals from overheating.
Thermex-Thermatron RF Heat Sealing Tips — Keys to Checking RF Heat Sealing Equipment Before & After Use

RULE #6: KNOW WHEN TO REPAIR DIES AND WHEN TO RETURN THEM TO THE MANUFACTURER

Some RF electronic heat sealing dies will call for repairs, but not all repairs are alike. For the swift and easy adjustments, like superficial nicks and arcs that aren’t quite as large in scope as you need, soft solider can offer simple resolution. However, when a die has experienced severe damage, send it to the manufacturer to diligently navigate the complex repair process for you. 

  • Slight nicks and small arcs are easily repaired with soft solider. 
    • Step one: After filing the burn, fill to the same level as the rest of the brass. 
    • Step two: If using a one (1) piece beaded seal insert, a piece of 2PT steel rule in the channel, then solider the hole. 
  • Return a badly burned, damaged die to the manufacturer for a complete repair and re-machining. 
  • Keep dies and buffer free of carbon at all times.
    • Use MEK or other cleaner for this purpose.

RULE #7: POLYETHYLENE SLIP SHEETS — THE SECRET TO NOT HAVING TO WELD INDIVIDUAL LAYERS TOGETHER 

By using polyethylene, Mylar, or polypropylene, you can tear seal two (2) or more individual layers of material without welding them together.

RULE #8: RECOMMENDED MATERIALS AND PLACEMENT OF BUFFERS

Your buffers must cover the aluminum plate of the trays or bedplate for you to be able to concentrate welding heat in the plastic. The following materials are preferred by most users, cost-friendly, or the best choice for non-stick applications: 

  • Fish Paper and Mylar are the most popular and inexpensive materials used.
  • For special applications, fiberglass may be used for its non-sticking properties.

RULE #9: WHEN STORING YOUR DIES: TREAT YOUR TOOLS WITH CARE

Investing in tools crafted to exact specifications, it’s essential to handle each material with meticulous consideration. Remember that your tools are precision-made and should be treated as such. 

  • Check dies for nicks and burns before storing.
  • Repair immediately or return them for repair and machining.
  • Store your dies in the container in which they were shipped, on clean shelves, and cover them with foam rubber.
  • Do not store anything on top of the tools.
  • If you must stack the boxes of dies, be sure to put several layers of foam between the tools.
Thermex-Thermatron RF Heat Sealing Tips — How to Carefully Store RF Heat Sealing Dies

RULE #10: AVOID BUBBLES AND OTHER SEAL FLAWS WITH FOAM PADDING

Dies are packed with foam for an advantageous reason: to force the air out between layers of vinyl before sealing. This in effect eliminates air pockets in the finished product.

Should you seek additional pressure, you can add it to the foam by gluing chipboard layers to the foam. This becomes especially easy when you use a chipboard stay in the sealed part.

PIONEER EQUIPMENT FOR INDUSTRIAL MANUFACTURING TRAINING, HEAT SEALING, AND WELDING 

Thermex-Thermatron offers parts and support services to help train and equip industrial manufacturers to always keep their products in an excellent state. Notably, in 1939, what would eventually become the Thermex Corporation produced in Louisville, Kentucky the original RF heating system for industrial applications. Industrial manufacturers have learned to rely on the Thermatron legacy for pivotal RF heat sealing and welding needs. Those who first used our groundbreaking equipment over 80 years ago continue to do so in a multitude of applications: fabrication, research and development, adhesives, wood-metal bonding, lumber edge bonding, furniture, ceramics, plastics, food, and shoes. 

For assistance in pricing and availability on these or any other parts, please contact our purchasing department: (502) 493-1299 ext. 208 [email protected]

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