Understanding Die Cutting Costs

Die cutting costs are driven by three main factors:

  • Material Selection
  • Processing Equipment
  • Form Factor or Part Presentation

Material Selection

The material (or materials) that will be die cut are typically the largest percentage of the overall cost of the part,usually 50-75 percent. Sometimes, the materials are specified on a print after they have undergone testing, or some selection process, by an engineering or technical function to determine their suitability for the application.

In other instances, you might only know what the die cut part needs to do in the end use, but not what material is necessarily the best option. Here’s where a converter can bring real value. They can recommend high performance options, “workhorse” type options and less expensive options. They can often be presented in a good, better, best sequence for performance and price to help make sure the part is over- or under- engineered.

Processing Equipment

Typically, converters  have more than one die cutting process. There are rotary presses that have very high output, but  more expensive dies and size limitations. There are flatbed presses that are typically slower, but have lower tolling costs. And there are waterjet/flash knife/laser cutting systems that have no tooling costs, but are more suitable for lower volume production or large format parts that can’t be processed on smaller equipment.

Form Factor/Part Presentation

 Do you need individual, discrete parts, or parts kiss cut on a common release liner in a pad or a roll?  Do you need the “slugs” removed (the part of the die cut that is “waste”), or a dry edge or “finger lift” added to make it easier to remove the release liner after installation?

All of the above factors play a role in determining the costs associated with die cut parts. Keep in mind the concept of total applied cost. Sometimes, you might invest a bit more upfront only to get a return later on reduced labor and higher throughput.

Want to know more about die cut parts for your assembly operation? Call Tom Brown, Inc. today!

Re-Glazing Curtain Wall Units With 3M Structural Glazing Tape

In our last blog post, we went through the process to de-glaze unitized and cassette curtain wall units that had been previously glazed using 3M’s structural glazing tape (SGT). The simple six-step process, developed by Project Vision Dynamics (PVD) in Plant City, Florida,  is a simple and safe process to get the IG units and frame apart to help keep your curtain wall installation moving along without losing excessive time. Now, we’ll walk through the re-glazing process and you’ll have the all the tools you need for success.

The SOP

The most important document you’ll get from 3M is the SOP (Standard Operating Procedure) that is tailored specifically for the exact IG and extrusion you are using in your project. That is the ultimate document to consult when re-glazing, but all SOPs follow the same basic seven-step procedure which are outlined below:

  1. Clean the extrusion
  2. Prime the extrusion
  3. Apply the structural glazing tape
  4. Clean the IG unit
  5. Prime the IG unit
  6. Bring the IG unit and extrusion together
  7. Apply sealant at the corners

Cleaning the Extrusion

Place the deglazed extrusion on your workbench.  Clean the surface where the tape will be applied using a 70% isopropyl alcohol (IPA) /water blend using a two towel method. The two towel method is simple. Take two lint free towels and fold them into fourths. Wet one lint free towel well with the IPA, and have a dry, lint free towel in the other hand. Starting in one corner, wipe the IPA on the extrusion and follow about 8 inches behind with the dry towel. Don’t do any more than two legs of the extrusion before you unfold the towel and expose clean sides on each towel. Finish the last two legs of the extrusion. If for any reason the towels are excessively dirty, repeat the cleaning step again.

Priming the Extrusion

The most frequently used adhesion promoter is 3M’s AP111, but sometimes the SOP will specify Primer 94, depending on what paint system is on the extrusion. The AP111 can be applied via a dauber bottle, followed by a lint free cloth wipe, or you can wet a lint free towel and, using the two wipe method outlined above, follow the same procedure.

(Applying the AP-111 Adhesion Promoter)

Applying the Tape

Once you have applied the adhesion promoter, you have about a 10-minute window to apply the glazing tape. (If for some reason you get called away for more than 10 minutes, don’t panic! Just start over again at Step 1, and you’re good to go!). Apply the tape down each leg of the extrusion using an HTA (Hand Tape Applicator). Here are two tips to help you: Don’t push down on the HTA; just pull the HTA lightly in toward the inside of the extrusion, and let the SGT unwind naturally from your other hand. Don’t try to keep the tape under tension, which can stretch the tape.

(Applying the tape with the Hand Tape Applicator)

Once you apply the tape while also making sure the corners overlap, trim each corner with a sharp razor blade in a guillotine-like motion to create a nice tight fitting butt joint at each corner.

Using a j-roller, make two passes with the roller on each leg of the extrusion. You’re only trying to exclude air from the bond line on your first pass, so keep it nice and light! On the second pass, bear down a bit more using 15 pounds of pressure. (15 lbs. is really easy to achieve even for a smaller person).

You can set the extrusion aside at this point. If you’re going to apply the IG unit on another day, put a piece of masking tape over the butt joint at each corner to prevent the liner from lifting prematurely and hang the extrusion on a peg.

Cleaning the IG Unit

If you followed the deglazing procedure properly, you should have a fairly clean IG unit free of any excess tape or contamination. If you don’t, grab a lint free towel and wet it well with the IPA,  cleaning the glass with an additional cleaning using a scrubbing motion.

If your glass is clean, then you can go to the two cloth method as you followed in the extrusion step. Wipe all the way around each leg, doing two legs before unfolding and refolding your wipe, to a clean face before finishing the final two legs.

Priming the IG Unit

The adhesion promoter, AP115, for the IG unit is chemically different from the AP111 used on the extrusion. But, like the AP111, the application method is similar. You can use a dauber bottle, or  a wet a lint free towel using the two towel method again to apply the silane adhesion promoter.

 

(Applying the AP115 Glass Adhesion Promoter)

Joining the IG Unit to the Frame

If you’re re-glazing a cassette system, you’re typically going to leave the IG unit lying on the workbench, applying the frame from the top. If you’re re-glazing a unitized system, you will likely have the extrusion lying on the workbench, applying the IG unit from the top, as the unitized frames are much deeper than the cassettes.

In either case, once you have applied the silane adhesion promoter to the IG unit, you have a 10-15 minute window to join the frame and glass. In either case, wipe the red liner covering the tape with a lint-free wipe before proceeding, to make sure that no dust or contaminants are present.

Cassette Specific Procedure

With the cassette, you’re going to do a process called ”pig-tailing.” This is a simple process where you take a blade or utility knife and flick up the edge of the red release liner from each corner, pulling away about 3 inches of the liner toward the center of each leg, as seen in the diagram below.

(A Pig-Tailed Corner)

Once you have all the corners exposed, get your buddy, on the opposite end of the frame, and turn it over together to get the tape pointed down toward the IG unit. Using your fingers, lower the frame to help align the frame edges and the IG unit. Once aligned, press down once lightly on the corners to temporarily anchor it in place.

Now stand in the center of each leg and pull one end of the pig-tailed liner toward the center of the leg, at about a 45°angle, stopping at the center. Now grab the other end and pull toward the center in the same manner. You can use your fingers to lightly lift the extrusion away from the glass in the center of the leg to completely pull out the red liner. Repeat this step for all legs of the frame.

You can now push down once by hand around the frame perimeter to position everything properly. You will then take the Developmental Industries SGT-PPA 150 pressure-applicator, set at 80 PSI, and make two passes down each leg of the frame/glass composite, to achieve good tape wet out and immediate handling capability. See diagram below.

Unitized Specific Procedure

Since the unitized system will likely be larger, you will not be following the pig-tailing procedure as with the cassettes. You will completely remove the liner from each leg of the extrusion and then lift the IG unit using a suction cup device to safely lift and move the IG unit into place as in the diagram below.

(Positioning the IG unit over a Unitized Frame)

At this time, the Developmental Industries pressure applicator does not work on deep unitized frames. This problem will be solved in the very near future as the folks at PVD have developed a new pressure applicator that works on deeper frames. In the meantime, you can use an Irwin Quick Grip Bar Clamp, that can be purchased at any hardware store, and work your way around the unit until you have applied a clamping force all the way around. One caution: some of these clamps can generate 600 lbs. of force which will crack the IG unit. You only need enough force to wet out the tape – typically the 100-150 lb. range is more than enough.

Apply the Sealant at the Corners

The last step is to gun a thin bead of sealant around each corner (3-4” around each corner) of the frame where the tape/frame/glass interfaces, and tool it into place. This can be done with specific spatula-type sealant tools, a wooden tongue depressor, or if all else fails, your fingers.

A one part, neutral cure silicone sealant is preferred, but any gun-able waterproof sealant will (technically) work.

You’re done! With just a little practice, a cassette can be deglazed and re-glazed in under an hour. A larger unitized system will take a bit longer. Still have questions? Contact Steve Sherman at PVD (www.projectvisiondynamics.com) or Rick Alexander at Tom Brown, Inc..

Deglazing Curtain Wall Systems Using 3M Structural Glazing Tape

Deglazing is never a popular topic when it comes to curtain wall or window wall systems. But sometimes, things go wrong and you can’t afford to wait 8-12 weeks to get new IG units or extrusions. You have to deglaze the affected units to meet your deadlines. Fortunately, the folks at Project Vision Dynamics (PVD) in Plant City, Florida,  have come up with a very practical approach that is safe, easy to follow, and requires no exotic tools,.


Step by Step

PVD trained us to deglaze both a unitized system from Kawneer (2500 series) and an Oldcastle Reliance Cassette. The method is the same for both systems:

  • Pre-tape (mask) the perimeter of the glass where it meets the extrusion using 3M Blue Painter’s Tape or other masking tape to help prevent scratching of the IG unit. (see photo below)

  • Get yourself a hand-held reciprocating undercut saw, with some 1.25” fine blades or a mushroom head blade, AND the magic ingredient– Mean Green Auto and Garage Cleaner and Degreaser. You can buy it at Lowe’s for about $8 per gallon. You’ll need a spray bottle to apply the degreaser. (see photo below)

  • Spray the degreaser into the glass /extrusion interface about 3” from a corner and insert the undercut saw. Go slowly and work towards the corner, keeping the interface lubricated enough to keep the saw blade moving smoothly Here’s the important tip….keep the saw blade cutting as close as possible to the glass surface. The tape is 90 mils thick, and the thicker you leave the tape on the extrusion, the easier it is to remove it in the next step.

  • Insert shims or wedges into the corners as you go along to make the undercutting easier.

  • Once you have undercut the entire perimeter, remove the frame from the IG unit and begin to “stretch release” the tape by loosening an edge with a razor blade,  pulling slowly towards you at roughly a 45° angle. This tape is a cousin to the “3M Command” brand of hooks and removes in a very similar fashion. Any problem areas can be cleaned up by spraying more Mean Green onto the area and using the razor blade to scrape away the tape.
  • Finally, clean the glass and extrusion using 3M’s Citrus Based Adhesive Remover to prepare for reglazing.
(Final Cleaning using 3M Citrus Based Adhesive Remover)

And that’s it! It takes a little practice, but we deglazed both the unitized system and the cassette in less than 30 minutes. If you need any further assistance, you can call Steve Sherman, at PVD, (he’s the Yoda of the curtain wall world … only taller!) or Rick Alexander, at Tom Brown, Inc.  (www.projectvision dynamics.com)

 

Materials and Tool List

  1. Reciprocating undercut saw and blades
  2. Mean Green Auto and Garage Cleaner and Degreaser
  3. Straight edge razor blades (and holders for safety)
  4. 3M Citrus Based Adhesive Remover
  5. Plastic or wood shims
  6. Wiping towels (don’t have to be lint-free, but it doesn’t hurt)

 

3M 4918 for Glass to Glass Partition Bonding

Thick film acrylic adhesive tapes are ideal alternatives to sealants for glass to glass partitions and shower enclosures. They provide a nearly invisible bond line and a durable, high strength bond that is attractive and easy to apply.

Part of the VHB Family

3M 4918 is an 80 mil thick, clear, viscoelastic core that is designed for bonding glass and other transparent materials. There are two sister products-4905 (20 mil) and 4910 (40 mil) that are the same acrylic core but in different thicknesses so you can pick the right product for the job. These products offer outstanding solvent resistance, adhesion to high surface energy materials such as glass, and have excellent temperature resistance up to 300°F.

Benefits to Your Customer

While high performance physical properties are important, what counts more is the value the product brings to the installer and the owner.

  • Easier to install than gunnable sealants
  • Uniform, invisible sight line
  • Better visual aesthetics than extrusions
  • Outstanding static shear resistance
  • Durable adhesion even at elevated temperature and humidity
  • Great shock and stress absorption properties

And Tom Brown, Inc. has it!

4918 is no longer offered by 3M in North America but Tom Brown, Inc. has log roll inventories in our Pittsburgh and Salt Lake City plants. We will convert to your specification-whether in slit roll form or die cut parts. We also offer the 4905 and 4910. Need to get some quickly for your project?  Give us a call.

 

Microcellular Polyurethane Foams

Microcellular polyurethane foams are everywhere and chances are, you don’t even know it. Pick up your cell phone, get in your car, or turn on your computer and odds are that microcellular polyurethane foam is there sealing and protecting against bumps, shocks, and isolating against vibrations.

What are Microcellular Polyurethane Foams?

Microcellular foams are designed to contain billions of tiny gas bubbles that are less than 50 microns (thus the name “microcellular”) in size. These foams are produced by dissolving  gases in varying amounts into the polymer under high pressure. A process called nucleation helps the bubbles or cells form into a fairly uniform pattern and the gas selected has a strong influence on the density of the resulting foam.

What does all that mean?

The resulting foams from the production process result in high performance materials that:

  • Offer excellent compression set resistance
  • Are highly resilient and will not collapse even after repeated opening and closing
  • Seal out moisture and are resistant to oils, greases, and aliphatic hydrocarbons
  • Noise isolation at high frequencies and vibration isolation at large amplitude and low frequencies
  • Maintain flexibility even in extreme conditions
  • Exhibit low outgassing and non-fogging properties
  • Are easy to die cut into intricate shapes

Microcellular Foam Applications

The number of applications and markets where microcellular polyurethanes are used is too large to list in one short blog post but some of the more popular applications include:

  • Electrical and electronic housings and enclosures
  • Cellular phones
  • Electronic gaskets
  • Instrument panels
  • Bumpers and pads
  • Automotive gaskets

Physical Properties

One of the premier manufacturers of microcellular polyurethanes is Saint Gobain. The densities available run for super soft to very firm. The workhorse K series data set is shown below to give some reference points for the more important properties.


Want to learn more about microcellular polyurethanes and what they can do for you? Contact Tom Brown, Inc. today.

(Photos and Data Table Courtesy of Saint Gobain Tape Solutions)

Understanding Architectural Panel Tapes

Architectural panel tapes (APT) are high performance double-coated acrylic foam tapes designed to replace rivets, welds, liquid adhesive systems, and other mechanical fasteners used in the fabrication of curtain walls, exterior cladding, and interior panel bonding and trim attachment.

The Benefits

The architectural panel tapes bring much more to the table than just replacing mechanical fasteners and liquid adhesives:

  • The viscolelastic properties of the tape absorb shock and flexing for reliable bonds against wind loads, vibrations, and thermal expansion and contraction.
  • The tape fills gaps to seal out water, dirt, and air.
  • The tape is invisible and hidden in the bond line. It doesn’t telegraph through the panel and enhances the appearance and beauty of the panel.
  • Tapes excel at joining dissimilar materials and permit the selection of a wider variety of materials for more stunning results. This includes painted metals, powder coated metals and hard to bond surfaces such as acrylic and polycarbonates.

The Proof is in the Performance

Architectural panel tapes have some formidable physical properties. Most people are stunned when they are given a demonstration part that is put together with APT. They simply can’t get them apart no matter how hard they try but the data is really what tells the story:

Applications

These tapes perform in both exterior and interior applications including:

  • ACM panel bonding
  • Exterior cladding and curtain walls
  • Interior column cladding
  • Stiffener to panel attachment
  • Clip bonding and attachment
  • Mirrored and glass ceiling tile attachment
  • Trim bonding

Want to learn more about APT or get some samples to try? Give Tom Brown, Inc. a call today!


Silicone Rubber Products for High Performance Applications

Silicones are a large family of elastomers with a unique chemical structure that  gives them superior high and low temperature capabilities that are unavailable in other families of elastomeric materials.

Silicones are very inert and, therefore, resist sunlight, ozone, oxidation, water and various chemicals. They contain no acid-producing chemicals and do not initiate corrosion.

Thermal Stability

Silicone’s physical performance properties are not affected by prolonged exposure to low temperatures (100°F), or high temperatures (+500°F), and can even withstand intermittent exposures to higher temperatures. (see Figure A below)

Silicones far outperform other elastomers in general service life, compression set resistance, electrical strength, and non-stick properties. They also exhibit good chemical resistance. Some solvents, such as gasoline or aromatic hydrocarbons, may cause temporary swelling of the polymer. But the material will return to its original dimensions after evaporation.

Variations

Silicones are available in solid rubber, sponge and foam rubber forms with a variety of  durometers. General purpose silicone rubber is extremely versatile and is often the best choice for applications involving high heat and pressures.

Silicones can be modified with fluorinated compounds to improve chemical resistance and phenyl chemistry to drive low temperature performance even lower to -130°F.

Fillers can be added to gain electrical conductivity, thermal conductivity and flame retardant properties. Fiberglass reinforcement can be added to improve dimensional stability.

Figure B below shows the compression-set comparisons for various grades of silicone rubber, sponge and foam.

Adhesive Options

Silicones exhibit low surface energy, which can make them a bit tricky to laminate with adhesives and achieve good anchorage. Tom Brown, Inc. has the know-how to modify the surface to permit lamination with either silicone or acrylic adhesive systems for gasket attachment or general bonding. Silicone pressure-sensitive adhesive exhibit temperature performance similar to that of the silicone elastomer (100°F to +500°F). Acrylic adhesives are a cost-effective option for some applications, but you trade away some of the temperature range. These adhesives will typically work in the -20°F to +350°F range.

Want to know more about silicone elastomers? Contact Tom Brown, Inc. today for samples, technical data, or to discuss your specific application.

(Photos and table courtesy of Saint Gobain Tape Solutions)

Unique Material Combinations- A Case Study

One of the fun things about working with large curtain wall manufacturers is that they are always looking to try new designs and concepts. That can make being a supplier a little bit of fun, too, to say the least. Sometimes you get to try “outside the box” ideas and let your customer see what you have created for them.  This is one of those stories.


Background

One of our curtain wall customers was designing a system for the new Salt Lake City Airport. In case you didn’t know, the current airport serves 23 million passengers a year in a 50-year-old facility designed for half that amount of traffic. This large project will generate over $3.6 billion in economic impact over the life of the upgrade.


Our customer needed a soft-foam product that could act as a water and air seal.  He really wanted the foam to be skinned with silicone for compatibility with other structural sealants that would be used in an expansion pocket.


The Solution

If you just try to search for silicone-skinned foam using a Google search, you will note a few silicone-foam products with smooth skins designed for other applications. There is no readily available solution. So, our CEO, Kenny Brown, took it upon himself to try something different. From past experience he knew that Saint Gobain produces an excellent low density foam, the V730 series. The V730 has some very useful properties including:

  • Sound transmission and vibration controls
  • ow thermal conductivity improving energy efficiency
  • Excellent seal against dust, light, and moisture
  • Closed cell structure for  a positive seal at 30% compression
  • Low deflection force reducing distortion of any adjacent materials

Next, he took a self-leveling silicone sealant from DowSil and applied approximately 20 mils on top of the ¾” thick V730 foam. He  cut it into blocks using a Waterjet cutting table.


A simple but elegant composite fills the expansion pocket with a high performance water and air seal. And  it is completely compatible with other primary sealants that will be used in constructing the façade. And yes, it looks very much like a gray brownie!

Have an application that requires a unique material solution? Contact Tom Brown, Inc. today to discuss how we can help.

High Performance Polyurethane Foam Tapes

I always feel a little sorry for polyurethane foam tapes. Why? They tend to get lost in the shuffle between the acrylic foam tapes on the one side, and the lower cost polyolefin foam tapes on the other.

Despite this, polyurethane foam tapes have some formidable physical properties and have an excellent performance to cost relationship.

What are Polyurethane Foam Tapes?

Polyurethane foam is produced by reacting polyols with diisocyanates to create highly resilient foams that we use every day in mattresses, car seats, and foam for tapes and gaskets. Various additives are incorporated to help tailor the urethane for particular applications.

These foams are coated acrylic adhesive systems that yield a high performance bonding tape that can:

  • Dissipate energy and stresses along the entire bond line
  • Resist weather, extreme temperatures, UV light, and fungus

One of the premier manufacturers of polyurethane foam tapes is Saint Gobain. They produce an excellent range that includes the V2800, V4600, and V8800 for severe exterior applications, V1300 for interior applications, the V900 series for electronic applications needing a UL rating and the Z500 series for automotive applications.


V2800 Series Physical Properties


Pay particular attention to the high dynamic shear and dynamic tensile values. These high values translate well into bonding tape applications for roof bows and panel stiffeners in truck and utility trailers and RVs,

  Other applications for polyurethane foam tapes include:

  • Body side molding
  • Wheel weight attachment
  • Composite panel bonding
  • Emblems and nameplate attachment
  • Sign framing
  • Wheel well and door edge moldings
  • Bumper trim and inserts
  • Rocker panels

Polyurethane foam bonding tapes might lack the popularity of the acrylic foams and polyolefins, but they perform reliably in heavy duty applications every day. They have an excellent cost benefit balance and should be considered for your next high performance assembly application. Want to know more about polyurethane foam tapes? Contact Tom Brown, Inc. today!

Foam Tapes for Muntin Bar Attachment

Simulated divided lites are a popular design option for residential and even light commercial windows. The design intent is to create the look of individual panes of glass by applying muntin bars or grilles internally (called “G-B-G” for glass/bar/glass) or externally by using foam bonding tapes. Muntin bars attached with high performance tapes having a pleasing visual appearance, have secure bonds if installed correctly, and save production time.

Types of Foam Tapes for Muntin Bar Attachment

The two most common types of foam tape used for bar attachment are acrylics and polyolefins.

Acrylic Tapes

Acrylic foams include the popular VHB brand from 3M and the Norbond brand from Saint Gobain. Other suppliers of high quality acrylic foam tapes include the AS series from Scapa, the ACX series from Tesa, and the SFB series from Avery Dennsion.

These tapes can be monolithic meaning the adhesive and foam core are extruded in simultaneously in a single layer or they can be multi-layer where an extruded acrylic foam core is coated with the acrylic adhesive system. In either case, these tapes exhibit excellent viscoelastic behavior. This means the “viscous” behavior allows the tape to absorb and damp energy that occur from sudden wind gusts or other forces while the elastic behavior allows the tape to recover (think of stretching a rubber band and then letting it come back to its normal shape).

 

Saint Gobain A7300 Series Performance Data

Polyolefin Foam Tapes

Polyolefin foam tapes are made from a foam core extruded from polyethylene that is often modified with varying amounts of EVA and polypropylene. Additional coatings can be extruded onto the foam core to create a very smooth surface onto which the acrylic adhesive will be coated. High quality polyolefin foams are produced by Adhesives Research as well as Berry Plastics, Adhesive Applications, and others.

The polyolefin foams don’t have the same viscoelastic behavior of the acrylic foam tapes but they exhibit very good dynamic shear and tensile (T block) values along with a very favorable price that can make them worth considering especially for lighter weight muntin bars made from cellular PVC and other lightweight materials.

Adhesives Research 8645 Muntin Tape Performance Data

 

Foam Core Stress /Strain Capabilities

The chart below demonstrates the capabilities of each basic type of foam core and how they differ.

 

Want to know more about muntin bar tapes? Contact Tom Brown, Inc. today for samples, technical data, or to discuss your application further.