In the world of slot die coating, thin is in. Or, to be precise, thin AND accurate is in. According to Scott Zwierlein of Frontier, “roll-to-roll slot die coating has become the industry standard for extremely thin and extremely accurate coating.” Let’s take a look to see if it’s the right coating method for you.

“The use of slot die coating will increase because it has several advantages,” adds coating industry guru Dr. Edward Cohen. These include attributes such as excellent quality and uniformity, and the fact that it’s pre-metered so that all of the coating is applied to the substrate.

However, Cohen also notes that each converter has their own specific needs which will determine which coating methods should be used. So how do you determine if slot die is the coating method of choice for you?

There are too many casino games to count and always more, is the simple answer. A quick overview of the kinds of games you can typically expect from a casino V Slot Accuracy includes slots, poker, blackjack, roulette, scratch cards, bingo, keno, craps and baccarat, to name but a few. A slot milled in a single step will not have a perfectly square form due to the direction of the cutting forces and the tendency of the tool to bend. The best accuracy and productivity will be achieved if the operation employs an undersized end mill, and is divided into two steps: Keyslot milling – roughing of full slot. For example if the warehouse management system indicates that 10 units of part number XYZ are in slot B0029, the inventory count accuracy indicates, depending on your choice of measurement criteria, either the percent of correctness or how frequently one can go to that location and find that the physical count matches the system’s on hand.

Let’s take an in-depth look at the technology and the uses to find the answer. (Full disclosure – Scott and Frontier are a subsidiary of Delta ModTech.)

How Thin is Thin and How Accurate is Accurate?

The fields of electronics, medical devices and pharmaceuticals continue to push the envelope, or should we say, the tolerances required for converters. At some point, their needs have exceeded the capabilities of traditional extrusion dies, and entered into the realm of the nearly infinitesimal.

Slot die coating can meet these new thickness and accuracy requirements. Just how thin can slot die go? With a slot die, Zwierlein explains you can achieve an attainable wet coating thickness of <2 micron. (NOTE: Slot die can be used to coat thick as well — we’re just highlighting the thin capabilities in this post.)

To put that in perspective, a “micron,” which is the abbreviated term for “micrometers,” is one millionth of a metre (or one thousandth of a millimetre, 0.001 mm, or about 0.000039 inch). A human hair is about 75 microns across.

Here’s a picture of a carbon filament 6 microns in diameter, overlaid on a human hair 50 microns in diameter.

Replacement bearings for v-slot style linear bearing systems. Machined out of aluminium to a high precision, these bearings have a high quality black acetal coating to ensure smooth and accurate movement with minimal noise. Perfect for Formbot and Creality style 3D printers. Exterior diameter: 15.28mm/0.60inch Inte.

Photo of a carbon filament, 6 microns in diameter, overlaid on a human hair, 50 microns in diameter. – Micro photo courtesy of Wikipedia.com

And how accurate is accurate? Accuracy in the coating world is flatness. Or, in other words, how much the thickness varies from your target. The attainable transverse web accuracy with a slot die is <2%.

Talk about little margin for error.

Now listen to this short audio interview with Scott Zwierlein, and then read on how slot die delivers on thin and accurate:

1. Extremely Thin

As Zwierlein notes, 2 microns is the “Holy Grail of liquid coatings.” Many traditional methods exist, but only slot die can achieve this level.

Why? It’s the nature of the equipment design. Other methods will flood a large amount of coating, and then wipe it away. Slot die does the opposite. It applies the exact amount to the substrate. Everything the pump delivers is applied to the substrate – there is no waste.

Other methods – such as reverse roll, knife over roll, and comma coating – use a device to wipe away excess coating leaving just the thickness desired. In this scenario you’re requiring a blade or bar to be positioned2 microns away from a substrate. “That’s almost impossible,” Zwierlein said. Take a look at the photo of the human hair above and you’ll see what he means.

2. Extremely Accurate

Accuracy is based on the amount of material you want to put down, how close you are, and how uniform you want it to be. Zwierlein explains that you might be able to achieve 2 microns with other methods, but you can’t match the accuracy of slot die.

With other coating methods the gap set for the blade or the bar is fixed and the substrate and coating fluid pass through it. If the substrate thickness varies, the thickness will vary. “The substrate you coat on is never that flat,” he said.

The Important Attributes of Slot Die Coating

A number of attributes need to be present to help slot die deliver on its promise. These attributes result in significant benefits over traditional methods in terms of functionality and cost savings.

1. Precision pre-metered fluid delivery

2. Extremely flat and straight die surfaces

3. High-precision backing roll

4. Accurate and precise positioning of die to the substrate

5. Contamination-free environment

Industries for Slot Die Coating

Slot die is becoming increasingly necessary in a number of industries. Here are just a few specific applications:

Micro-electronics: Flat panel displays, thin circuits.

Batteries and capacitors: Lithium-ion battery electrodes, multilayer ceramic capacitors.

Barrier films: In food and medical packages, liquid film coatings are being applied to food coating.

Solar photovoltaic: Solar cells require thin coatings.

Medical diagnostics: Chemistries and other solutions need to be accurately applied. Variations in thickness can result in variations in results.

Transdermal and oral pharmaceuticals: The more accurate you coat the transdermal, the more accurate the dosage.

Now let’s take a specific look at two types of slot die coating that can deliver for these applications:

Stripe Coating

Stripe coating is the preferred method when you are producing a narrow strip with exposed foil along one or both edges, in battery and capacitor applications for example.

Some requirements for good stripe coating include:

Uniform Coating Thickness

Proper cavity design is essential. You need proper die shim thickness for optimized die pressure; that produces the right uniformity for cross web production.

Accurate Width Control and Good Edge Quality

The shim sets width — it looks like a comb. Accurate shim design and fabrication is important to maintain the proper alignment. A die vacuum is used to fine-tune the width. The die vacuum also ensures there is no saw tooth or waviness.

Patch Coating

With patch coating, we’re expanding on the issues that make stripe coating desirable. It’s required when an uncoated substrate is required around the full perimeter of a coated part, not just on two sides or one side.

For example, on a touch screen or an LCD screen, you may have a grid of circuitry that requires leads to be exposed on the bottom and/or the sides. Transdermal patches require patches to be cut out of adhesives, and you don’t want to apply the medicine beyond the patch area.

Some requirements for good patch coating include:

Good Machine Direction Edges

The coating edges must be continuous, consistent and sharp.

Good Leading Edge

There can be no heavy build-up at the start of the patch. Accurate and repeatable timing is important – this is why it’s desirable to move the fluid, and not the machine. (Scott describes this method in the audio interview.)

Good Trailing Edge

The trailing edge should be straight and clean, no feathers or drip lines.

Uniform Coating Thickness Throughout Patch

Minimal variability is essential.

Here’s a graphic of a patch to illustrate some of the terms from above:

Slot Die Coating is a Huge Advantage for the Right Industries

As we noted earlier, industries such as electronics, medical devices and pharmaceutical keeping raising the bar. Converters looking to meet tighter tolerances are finding yesterday’s traditional extrusion dies can’t keep pace with the new normal.

If you’re in these uber-competitive industries, slot die coating can be the answer you’re looking for. And since “profitable” is always in vogue, it’s an advancement that will be welcomed with open arms.

Choose the right methodology for your next coating project.

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• Best Range Gear OSRS

Many people were not happy with the direction of development that RuneScape bosses have chosen. This gave birth to the Old School RuneScape with all its retro charm, special features, mechanics and, of course, the gear and the unique ways it works in a full set. It’s hard to choose the best range gear OSRS can offer simply because certain gear fits certain needs. Here are the selected, top-class contestants that desperately need your vote. OSRS best range gear is to be defined right here and now by the most hardcore players that have ever existed. Want to join the party?

Ring slot Archers ring (i) +8/ Archers ring +4.

An upgraded Archers ring OSRS range gear. It can be earned as a prize at the Nightmare Zone. 650,000 reward points is the price that you need to pay to get it. The imbued status will be lost if the holder dies in a PvP match, this doesn’t carry over to deaths in PvE, though.

V Slot Accuracy Vs

Shield slot: None/ Odium ward/ DFS

Depending on the weapon in use, you can increase your range armor in OSRS. Odium ward offers one of the best ranged attack bonuses, outmatched only by the Twisted Buckler. DFS, in turn, is often listed among the best shields in the entire game. It’s both an anti-dragon and anti-frost the same time.

V Slot Accuracy Chart

Weapon slot: Heavy ballista +120/ Armadyl crossbow +100/ Toxic blowpipe +60.

Let’s move on from the ranged armor in OSRS and discuss the weapon slot. Heavy ballista provides tons of damage, offers speed comparable to the Godsword and a Concentrated Shot special attack. Armadyl crossbow is notorious for the faith bonus and extended range. Toxic blowpipe is a dart weapon with stackable range, depending on ammo used.

Cape slot: Ava’s Accumulator +4

This OSRS ranged gear is rewarded through Animal Magnetism quest. It provides the wearer with the best ranged bonus that can be found in the game for this particular gear slot. It attracts random metal items and provides the ability to pick up ammunition when weapons are fired.

Amulet slot: Necklace of Anguish +15/ Amulet of Fury +10/ Amulet of glory +10

Regarding the amulet slot for OSRS range gear, we have three powerful items. Necklace of anguish requires 75 HP to wear and offers powerful offensive bonuses for the Ranged class. Amulet of Fury, on the contrary, focuses mainly on defense, strength, and prayer skills. Amulet of glory is cheaper but still provides decent attack bonuses.