Laser Safe Materials
Engineered materials include a wide range of synthetic and non-synthetic composites. These materials are often specialized and excel at specific applications. We’ve summarized the most common materials encountered and their notable properties.
Acrylic is a thermoplastic known by many names which include, Plexiglass™, Optix™, and Lucite™. Acrylic is a synthetic polymer of polymethylmethacrylate, or PMMA. There are many colors and thicknesses of acrylic that can be obtained for product parts.
Types of Acrylic
- Cast – More chemical resistant. Etching is white. Cast acrylic tends to be dense and is generally stronger compared to extruded acrylic; however, thickness tolerances are generally larger.
- Extruded – More affordable. Etched areas remain clear. Typically, this group of acrylics maintain a higher thickness consistency; however, it is generally less dense than when cast.
Advantages – When compared to glass: acrylic is just as clear, stronger, 50% of the weight, while being weather and impact resistant. Laser cutting acrylic results in a polished edge. Furthermore, acrylic can be printed upon with the proper coating for content for signage.
Some items to consider – Scratches easily. As the thickness of acrylic may vary, designs generally must compensate for some variance with tolerances.
Polycarbonate is a thermoplastic that frequently goes by its brand names of Lexan™ and Makrolon™. As the name indicates the polymer contains carbonate groups. Polycarbonate also comes in an optically clear form.
Advantages: Polycarbonate offers good UV protection and is more impact resistant than acrylic.
Some items to consider: Due to its high UV absorption, laser cutting is generally limited compared to acrylics. Cut edges may become discolored. Also with prolonged exposure to UV, may yellow, or the optical clarity may degrade.
High-Density Polyethene is common plastic used to day in products such as thin gauge carrier bags, fresh produce bags, and some bottle and caps.
Advantages: Low cost, resistance to moisture, some chemicals, and food grades are obtainable.
Some items to consider: High thermal expansion, poor weathering resistance, subject to stress, and flammable.
Delrin is an acetal homopolymer resin is a highly-crystalline engineering thermoplastic that industry leaders specify for high load mechanical applications, such as gears, safety restraints, door systems, conveyor belts and healthcare delivery components.
Advantages: Can withstand high load applications. Can be threaded and counter sunk by hand with specialized tools. Great for prototype testing. Due to its ductile nature, this is a great choice for tension fit components.
Some items to consider: When laser cutting Delrin, heat will melt the Delrin. Profile cutting and interconnecting joints must account for variances. Strong acids and bases will degrade this plastic.
Plywood is a composite containing multiple sheets of wood adhered together. Plywood consists of alternating grain laminates which are oriented to increase strength and rigidity in a desired direction. Plywood comes in many grades which are as follows:
- Grade B or I – This is the highest quality of plywood. B grade will exhibit the color and texture one looks for in that type of wood and is sanded smooth. It doesn’t allow holes or mineral streaks, or what the industry calls doughnuts. A doughnut is where the imperfection is cut out and replaced with a patch of the same wood. These areas will contain more adhesive.
- Grade BB or II – This grade allows doughnuts, but meets B grade in other aspects.
- Grade CP or III – A piece that has been grade out of BB and into CP because of small defects or mineral streaking. Furthermore, there may be an excessive number of doughnuts that classed it out of BB and into CP. One thing that is allowed in CP grade are hairline splits of 0.5mm or less.
- Grade C or IV – This grade is not sanded and intended for utility uses. This grade allows veneer splits, holes, and knots.
While the above grades exist, most are typically broken down into the following 2 ratings. One for the face and one for the back. For example, B/BB would have a very high quality face; however, the back will have some doughnuts.
Advantages: Frequently a cheaper alternative to solid woods. As an engineered material, plywood can offer great strength, aesthetics and is generally an affordable natural composite.
Some items to consider: Due to the adhesives it’s a good idea to wear a mask to protect yourself when cutting, sanding, or grinding. Material is generally flammable and absorbs water in its natural state.
Corrugated board, cardboard, and card stock. These materials are a composite of fibers and oftentimes adhesives.
Advantages: Material generally displays strong tensile strength compared to weight. Typically this group of materials are cost effective and have a wide range of uses. Great for prototyping or for disposable applications, such as CAD prototyping (Cardboard Aided Design).
Some items to consider: Corrugated and cardboards are rigid, but once bent, original rigidity is lost. Card stock generally has no compression strength, and this group of materials absorbs water.
A mesh fabric frequently used in the textile industry.
Advantages: Frequently used as accent fabric or to achieve the light and airy feel of dresses and in cosplay. Generally displays good tensile properties and has a wide range of weights and colors.
Some items to consider: Will fray if frequently pulled upon.
Engineered foams are polymers that foam around pockets of gas. Usually these foams are made up of polyurethane or polyethylene. Engineered foams come in two types. Closed cell and open cell.
- Open Cell – If a foam forms with open channels or cells between adjacent cells, this is generally considered an open-cell variety. These generally are light weight in nature and can be rigid or malleable with a range of densities. Open cell foams by nature allow for gas or water ingress.
- Closed Cell – A denser foam that encapsulates and traps gas inside the polymer during the manufacturing process. These cells are generally closed off from adjacent cells which create pockets of gas that compress when force is applied. These foams generally retain the original shape and are elastic in nature. Additionally they tend to resist water ingress and other environmental contaminants. Typically, this class of foam does not harbor mold, water, or bacteria.
Advantages: Foams are frequently used as a moldable core for fiberglass or carbon fiber molds. They are typically affordable and light weight; which has proven valuable to fill void spaces in the packing and shipping industries. They are shaped easily and have a high impulse or impact rating. Rubberized foams can be used as gaskets, seals, or to protect wear surfaces as a wear material.
Some items to consider: Foam generally does not handle abrasions, and that polymer holding it together can breakdown with strong acids or bases.
These materials are generally processed from natural sources and typically not a part of an engineered composite. One thing to consider with natural materials is that they are not consistent in nature due to how the materials are made. Grades do exist for most of these materials; however, even the top grades are not of a homogenous composition throughout the material, or from piece to piece.
A natural product that has beautiful feel and warmth in appearance leather is a great material with strong abrasion resistance and good tensile strength.
Advantages: pliable and flexible. Soft and smooth to touch.
Some items to consider: Needs to be protected if exposed to frequent UV light. Not weather resistant. Raw leather will absorb water and other fluids unless treated.
Wood that is cut from a single tree into boards or sheets.
Advantages: wide variety of options are available. Solid wood has a beautiful grain and color. Wood is highly versatile in its workability.
Some items to consider: Solid wood is limited in width by the width of the tree it was cut from. Material will have some discrepancies due to limbs, strange growth, or knots.
If you don’t see the material that you would like to work with above, please contact us to discuss your project and your material requirements.
* Note that sheet materials have stated thicknesses; however, the actual thickness of the material may vary based on the manufacturing process. Whenever possible, we will note if the stated material thickness has any variances to known dimensions and the overall tolerances as noted per the manufacturer.
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