• When to Use Rubber and When to Use Urethane

    The following is a guest post by Mark Tool & Rubber located in Franklin, LA.

    In the oilfield and wastewater business, splash zone water erosion and unmanaged rust are big problems that can jeopardize operations and lead to huge financial losses. That’s why elastomers, also known as industrial “rubbers,” have been used to coat pipes for nearly a century. They were the standard coating for nearly all pipes until the introduction of polyurethane coatings more than half a century ago.

    Splashtron

    High-density elastomer Splashtron coating has been used to coat pipelines for over 30 years, up to depths of over 1,000 feet. Splashtron is great because it:

    • Bonds strongly to metal
    • Bends with its surface — it will never crack or disband as a pipe flexes
    • Shields from saltwater and oxygen; features exceptional durability
    • Resists buildup of scale, fungus and sea life; is easy to clean
    • Is a great electrical insulator
    • Absorbs shock and resists impact damage
    • Lasts indefinitely

    Premium Splashtron coating isn’t for everyone, and it isn’t necessary for all purposes. Some simpler jobs call for simpler, more affordable coatings, and that’s when this rubber and polyurethane enters the picture.

    Rubber vs. Urethane

    Customers regularly ask about the difference between rubber and urethane options. In order to explain how they’re different and the pros and cons of each, let’s look at their benefits, first:

    Advantages of Custom Molded Rubber

    • Very strong; less rigid than other materials
    • Withstands more stress and exhibits less wear
    • Acts as non-conductive insulator
    • Very affordable

    Advantages of Cast Urethane

    • Better strength, toughness, durability and versatility than rubber
    • Is better suited for specific applications than rubber (due to strength)
    • Has adjustable / customizable chemical properties for different applications
    • More affordable than Splashtron

    So, as you can see, the main difference between cast urethane and custom-molded rubber is cost. Polyurethane is all-around a better customizable solution, but rubber is quite simply more affordable — and both solutions are more affordable than the premium Splashtron coating for pipes.

    A better way to understand the difference between rubber and urethane is to determine which applications call for their use most often:

    Custom Molded Rubber Applications

    • Pipe Rollers
    • Tensioner Pads
    • Custom molded equipment

    Cast Urethane Applications

    • Forklift Pads
    • Pipe Line Supports
    • Pipe Spacers
    • Pipe Rollers
    • Push Knee Pads
    • Towline Protectors
    • UreGuard VIV Strakes

    Which should you use?

    As you can see, cast urethane has more applications than rubber due to its higher versatility, strength, and durability. But rubber is still the material of choice for simpler applications, like pipe rollers and tensioner pads. Rubber is also preferable for custom-molded equipment.

    It’s difficult to truly distinguish between the benefits of each material and what you’ll need for your project given a specific budget.

    To help determine which is right for you, the specialists at Mark Tool & Rubber are available to answer your questions – give them a call at 337-828-4479.

    July 19, 2016 • Guest Posts, Maintenance • Views: 195

  • A Comparison Between Hollow Mold Inserts and Conformal Cooling

    Recently, a major plastic manufacturer who was capable of making in-house molds tried using a different method by making use of additive manufacturing (3D printing or digital layering) to make mold tooling. This experiment went on for over a year and the process of additive manufacturing, which included conformal cooling, was used to make injection mold inserts. The mold inserts were made using a powder-bed metal additive manufacturing machine, and curving internal cooling channels were used instead of the conventional drilled holes. However, the increase in cost for installation and maintenance was not worth the improvement in cooling. The manufacturer also had doubts if the usage of channels for passing water as it was not efficient.

    Modifications

    They have now modified it and made it hollow instead of channeled. The cooling medium gets circulated in the inner area. Similar to how additive manufacturing was able to grow an insert by curving around internal channels, an insert could also be grown using open internal space. Rather than having growing channels in between, leaving the internal geometry blank is a better idea as additive manufacturing results in a hollow form faster, and at a lesser cost when compared to the production of a solid part.

    The company was initially skeptical about using a hollow mold insert, as it is lightweight and they wanted the mold to withstand the high pressure of injection molding. In addition, they were in need of a heavy and substantial level of tooling. Finally, they came up with an important test using an injection mold core which was a 7-inch medical device. As per mathematical analysis, the usage of a thin walled hollow version core would give the required strength. Based on the analysis, they 3D printed the hollow core in tool steel for further testing purposes.

    Paying Attention

    A high level of attention was paid by the molding machine operator during testing. The lightweight insert was about to crack due to the molding pressure. However, the tool did not crack and it worked perfectly well. Although there were some glitches initially, the hollow mold tool worked in the later stages and proved to be highly effective and efficient. One of the key aspects about injection molding is that the majority of time required to manufacture the plastic part is the time to cool. To increase the productivity significantly, the best possible option would be to evolve the cooling process.

    Hollow Results

    When hollow mold was used, the molding cycle time using new tool cutting was 41.5 seconds, whereas 46.5 seconds was accepted previously for the same part. This is a significant improvement when compared to what a similar core with conformal cooling would have achieved even if the core was more solid. It would require more time and metal for production if an additive process was used. Also, some of the other potential improvements that were experimented during the first test will be incorporated in the later stages to further reduce the molding cycle time.

    May 4, 2016 • Industry News, Machining Tips • Views: 319

  • Submicron Measurement in Manufacturing

    There is a necessity for pinpoint precision in the field of manufacturing. The machining centers available have the capability to cut ultra-high precisely and the expensive grinders that cost a fortune are operated by machinists who are highly skilled. Also, there is a lot of effort, money and time involved when a part of the machine has to be brought to the lab, spare time until a gage block stack normalizes to room temperature before taking the measurement.

    Due to the usage of ultra-high precision shop owing to the high investments made, submicron measurement is now feasible. The root measure to be taken for manufacturing to be done at a submicron level is to eliminate the temperature variations that exist. The effects of motors and coolant present in the machine also need to be taken care of.

    Measurement in terms of submicron is possible by making use of a universal measuring machine that is stationary and has a high level of precision. It is a robust and reliable instrument that can measure in submicron and can eliminate the disadvantages caused due to Abbe error. There are different grades available in universal measuring machines, with some having the capability to measure thickness of 0.5 to 0.01 micron gage block and master setting ring or disc measurement. Generally, machining on the shop floor is not stringent enough to when compared to the lab grade machines to precisely measure. However, a high precision measuring machine is available to facilitate precise measurements while in the manufacturing operation.

    To start with, the appropriate universal measuring machine to suit the requirements of manufacturing has to be chosen. It should at least be better by a factor of five when compared to the precision of the manufacturing machinery.

    On similar lines to how you determined the best location for your manufacturing machine for optimal performance and environmental control, the same procedure has to be followed for the universal measuring machine too. A thorough study has to be carried out to assess the presence of cold and hot spots, as even slight changes in temperature can be picked up by universal measuring machines, also doubling up as temperature indicators.

    Hence, before you place it, you will have to understand the pattern of airflow in your production area. Based on the same environmental conditions as that of the machine, you will have to place the universal measurement machine. You might also have to place a table with side walls all around the machine for aiding the control drafts. It is a nice idea to place a four-sided enclosure around it to ensure that there are no sudden temperature variations.

    As the machining process happens, there is bound to be coolant mist in the air even if you use high-end systems. At times when there is a machine clean or change over, the contaminants might get airborne and might enter the gage of the universal measuring machine. This should be taken care of on a regular basis to ensure that the measurements stay precise.

    April 26, 2016 • Cutting Tools • Views: 293