How to Choose Between Acrylic and Polycarbonate for Your Custom Manufacturing Project?

Choosing the right plastic for your project can be tricky. A wrong choice might mean wasted money and effort down the line. It’s frustrating when parts crack easily or end up costing more than expected. I'm here to help you understand the differences between acrylic and polycarbonate so you can pick the best one for your needs.

To choose between acrylic and polycarbonate, you need to look at impact strength, clarity, cost, and how easy they are to work with. Polycarbonate is much stronger and resists impacts better. Acrylic is often clearer and more scratch-resistant but can break more easily.

Making the right material choice is a big step in any custom manufacturing project. This choice affects how your part performs, how long it lasts, and, importantly, how much it costs. Let's take a closer look at these two popular plastics. By understanding their strengths and weaknesses, you can make a confident decision for your specific application.

Which is better polycarbonate or acrylic?

Are you stuck trying to figure out if polycarbonate or acrylic is the superior material? This confusion can slow down your project. Picking the one that's less suited for your job could mean part failure or spending more than you need to. Let's compare them directly to see which one really fits your needs best.

Neither polycarbonate nor acrylic is universally "better." Polycarbonate wins on strength and impact resistance, making it very tough. Acrylic offers better optical clarity, good UV resistance, and is often more affordable upfront, but it's more brittle. The best choice truly depends on your specific application requirements.

When I talk to customers like Mark Chen from Canada, who needs durable CNC machined parts at a competitive price, the "which is better" question comes up a lot. There is no single answer because it really depends on what you need the part to do and the environment it will be in. Both materials have their place.

Key Differences: Acrylic vs. Polycarbonate

Think carefully about where your part will be used and what it needs to do. If you need a super clear display case that is unlikely to get hit, acrylic could be perfect. If you need a machine guard to protect people from flying debris, polycarbonate is the much safer and stronger choice. I always tell my clients to list their "must-have" properties first, and then we can see which material lines up best.

Is acrylic or polycarbonate easier to machine?

Are you worried about machining challenges with plastics? Choosing a material that's difficult to machine can cause headaches. It can mean higher costs for you and potentially damaged or out-of-spec parts. So, let's look at which of these plastics, acrylic or polycarbonate, is generally easier to machine.

Acrylic is generally easier to machine than polycarbonate. It tends to cut cleaner and can produce better surface finishes with standard tooling. Acrylic is also less prone to melting or burring if you use the correct speeds and feeds. Polycarbonate needs a bit more care during machining.

At Worthy Hardware, we machine a lot of both acrylic and polycarbonate parts for our customers all over the world. Based on my years of experience, while we can successfully machine both to very high standards, they do behave quite differently on our CNC machines.

Machining Considerations

Acrylic (PMMA):

• Cutting: Acrylic can sometimes chip if you're not careful, especially with the wrong tool or feed rate. But with sharp tools and the right settings, it gives a very clean, almost polished edge. In some ways, it's a bit like machining a very hard wood.

• Melting: It has a lower melting point than polycarbonate. This means you need to manage heat buildup during machining. Too much friction from a dull tool or slow feeds can cause it to melt and gum up the cutting tool. Using coolant or an air blast helps a lot.

• Tooling: Standard high-speed steel (HSS) tools can work, but carbide tools are better for longer life and finish. Tools specifically designed for plastics, with special rake and clearance angles, give the best results.

• Finish: With the right machining techniques, you can get a very smooth and even optically clear finish directly from the machine. This can sometimes reduce or eliminate the need for later polishing steps.

Polycarbonate (PC):

• Cutting: Polycarbonate is much tougher than acrylic and more resistant to chipping. However, it's more prone to burring. This means a little lip of material can form on the edge of the cut, which then needs to be removed.

• Melting: Polycarbonate also melts with too much heat, but it tends to get gummier than acrylic. It can stick to the cutting tool if heat isn't controlled well. This requires very careful selection of cutting speeds and feed rates.

• Tooling: Sharp carbide tools are strongly recommended for polycarbonate because of its toughness. Sharp tools are really critical to avoid too much heat.

• Stress: Polycarbonate can be more likely to develop stress cracks if it's exposed to certain cutting fluids or if there are high internal stresses from the machining process. Sometimes, for critical parts, an annealing step (a gentle heating process) after machining is needed to relieve these stresses.

So, if ease of machining is your absolute top priority and the part's other property requirements allow it, acrylic might be the simpler choice for your CNC machining project. However, at Worthy Hardware, we have the expertise and advanced equipment, like our 5-axis CNC machines and precision machining capabilities, to handle the trickier aspects of polycarbonate machining. We can achieve very tight tolerances, even down to +/- 0.001 inches, and we make sure all sharp edges are properly deburred by default.

Is acrylic or polycarbonate better for greenhouse?

Are you planning to build a greenhouse and feeling unsure about the best glazing material? The material you choose directly impacts plant growth and the durability of your structure. The wrong material could lead to poor light conditions, too much heat loss, or easy damage from things like hail. I’ll help you decide if acrylic or polycarbonate is the better choice for greenhouse panels.

Polycarbonate is generally better for greenhouses. It offers much greater impact resistance against hail and falling debris. It also provides better heat retention and good light diffusion for plants. While acrylic has slightly better initial light transmission, polycarbonate's overall durability often makes it the preferred choice.

I often get questions from people about materials for outdoor applications. Greenhouses are a classic example where the choice between acrylic and polycarbonate is very important. While my company, Worthy Hardware, focuses on manufacturing custom CNC machined parts rather than selling greenhouse panels directly, the material properties are something we deal with every day.

Greenhouse Glazing: Acrylic vs. Polycarbonate

From my experience and understanding of materials, polycarbonate's toughness is a massive advantage for greenhouses. Imagine a severe hailstorm – acrylic panels might shatter, leading to expensive replacements and potential damage to your plants. Polycarbonate can usually take that kind of abuse without breaking.

Also, the way polycarbonate diffuses light can be very beneficial for plants, providing more even lighting throughout the greenhouse. While acrylic offers excellent initial clarity, for the demanding environment of a greenhouse, polycarbonate, especially UV-stabilized and multi-wall types, often wins out for long-term performance and peace of mind.

What are the disadvantages of polycarbonate?

Are you considering polycarbonate for your project? It's a fantastic material, but you need to know its downsides before you commit. Ignoring potential disadvantages can lead to unexpected failures, performance issues, or a final product that doesn't meet your expectations. Let's uncover the potential drawbacks of using polycarbonate.

The main disadvantages of polycarbonate include its lower scratch resistance compared to acrylic, its tendency to yellow from UV exposure if it's not specifically treated for UV resistance, a generally higher initial material cost, and its potential for stress cracking when exposed to certain chemicals or if improperly processed.

Polycarbonate is an amazing material. It's incredibly tough and versatile. I’ve seen it used in everything from nearly indestructible machine guards to critical aerospace components that we've manufactured here at Worthy Hardware. But, just like any material, it’s not perfect. It's really important to understand its limitations so you can make an informed choice.

Potential Downsides of Polycarbonate

1. Scratch Resistance: This is probably the most common issue people mention. Polycarbonate scratches more easily than acrylic, and much more easily than glass. For applications where visual clarity and a pristine surface are very important, and there's a risk of abrasion (like display covers or lenses), this can be a significant drawback. However, special hard-coated polycarbonate options are available. These coatings greatly improve scratch resistance, but they do add to the material cost.

2. UV Degradation: Standard, untreated polycarbonate can yellow and become more brittle over time with prolonged exposure to ultraviolet (UV) radiation from sunlight. For any outdoor applications, it is crucial to use UV-stabilized grades of polycarbonate or ensure it has a UV-protective coating. Many polycarbonate sheets designed for outdoor use, like those for roofing or greenhouses, already have this protection built-in.

3. Chemical Sensitivity: Polycarbonate can be attacked and damaged by certain chemicals. This includes some solvents, strong alkaline cleaners, and even some types of cutting fluids used during machining if they are not chosen carefully. Exposure to incompatible chemicals can lead to crazing (the appearance of fine surface cracks) or even cause the part to fail structurally. It's always very important to check chemical compatibility for your specific application and environment. I always tell my clients, like Mark, to clearly specify the operating environment for their parts so we can consider this.

4. Higher Initial Cost: Generally, the raw material cost of polycarbonate is higher than that of acrylic. While its superior impact strength and toughness often justify this higher price, for very budget-sensitive projects where high impact resistance isn't the primary need, acrylic might be a more economical choice upfront. However, as I mentioned, PC's durability can lead to better long-term value.

5. Processing Challenges: While polycarbonate is certainly machinable, it can be trickier to work with than acrylic. It requires careful control of machining parameters to avoid problems like melting, burring, and inducing stress in the material. It's also more sensitive to moisture absorption. If polycarbonate absorbs moisture from the air, this can cause issues like bubbles if it's later heated for thermoforming or injection molding, unless it's properly dried beforehand.

Despite these points, for a huge number of applications, polycarbonate's strengths, especially its incredible impact resistance, far outweigh these disadvantages. At Worthy Hardware, we work closely with our clients to mitigate these issues, for example, by recommending specific grades of polycarbonate, suggesting appropriate surface finishes, or optimizing machining processes.

Which is easier to bend acrylic or polycarbonate?

Do you need to bend plastic sheet for your design? Choosing the wrong material can make this process very difficult or even impossible. The material might crack, not hold its shape correctly, or require specialized equipment, wasting your time and resources. So, I'll explain which plastic bends more easily: acrylic or polycarbonate.

Polycarbonate is generally easier to bend, especially when it comes to cold bending (bending without heat). It is much more ductile and can be bent to tighter radii without cracking. Acrylic almost always requires heat for bending (a process called line bending or heat folding) and can easily crack if bent cold or stressed too much.

Bending is a very common fabrication method for creating shapes from plastic sheets. How acrylic and polycarbonate respond to bending is quite different. This is something we often consider at Worthy Hardware when discussing part designs with our customers. Even if we are primarily CNC machining parts, subsequent assembly or forming operations by the customer might involve bending.

Bending Characteristics: Acrylic vs. Polycarbonate

Acrylic (PMMA):

• Heat Bending (Line Bending): Acrylic almost always needs to be heated to be bent properly and permanently. This is typically done using a strip heater (also called a line bender). This device heats a narrow section of the acrylic sheet until it becomes soft and pliable. Once it's pliable, it can be bent to the desired angle and then must be held in that position until it cools and sets.

• Cold Bending: If you try to cold bend acrylic, especially if it's a thicker sheet or you're trying for a tight curve, it will usually result in it cracking or snapping. Acrylic is a relatively brittle material at room temperature.

• Spring-Back: After being bent and cooled, acrylic often has some "spring-back." This means it tries to return slightly towards its original flat shape. So, you might need to over-bend it a little bit to achieve the final desired angle.

• Stress: If acrylic is not heated evenly or is bent too quickly, it can induce stress in the material at the bend area. This stress might lead to crazing (fine cracks) appearing over time, especially if the part is exposed to certain chemicals or further stress.

Polycarbonate (PC):

• Cold Bending: One of polycarbonate’s big advantages is its ability to be cold-bent. Because it's so ductile and tough, thinner sheets of polycarbonate (up to about 3mm or 1/8 inch, depending on the bend radius) can often be bent at room temperature without any heating. They will hold their shape well. This is great for creating simple curves or angles quickly and easily, sometimes using equipment like a sheet metal brake.

• Heat Bending: For thicker polycarbonate sheets or when very sharp or complex bends are needed, heat bending is still used, similar to how it's done with acrylic. However, polycarbonate generally requires higher temperatures to become pliable. It's also important to control the heat carefully because polycarbonate can absorb moisture from the air. If moist polycarbonate is heated too rapidly, this moisture can turn to steam and cause bubbles within the material. Pre-drying the polycarbonate sheet is often recommended before heat bending.

• Tighter Radii: Polycarbonate can generally be bent to much tighter radii (smaller curves) than acrylic without fracturing. This is true whether it's bent cold or hot.

• Durability of Bend: Bends made in polycarbonate are very durable and strong, thanks to the material's inherent toughness. They are much less likely to crack or break at the bend point compared to acrylic.

So, if your design involves simple bends and you want to avoid the need for heating, polycarbonate is often the easier and more forgiving material to work with. For applications requiring very clean, sharp, and optically clear bends, like in retail displays, acrylic, when heat-bent correctly by experienced fabricators, performs very well.

I always advise my clients to consider the bending requirements early in their design phase. If a part needs complex bends and must also have high impact strength, then polycarbonate is usually the go-to material, even if it means applying heat carefully.

Conclusion

Choosing between acrylic and polycarbonate really comes down to your specific project needs. Think hard about impact strength, clarity, machinability, and overall cost to make the best decision for your parts.