Which plastic is best for an electronics enclosure: ABS, PC/ABS, polycarbonate, nylon or polypropylene?

For most small electronics enclosures, start with ABS: it's tough (high impact resistance), inexpensive, easy to mold and takes a good finish. Choose another plastic when the product asks for it:

PC/ABS (a blend of polycarbonate and ABS, also written PC+ABS or ABS/PC) for more toughness, more heat resistance or a flame-retardant (UL 94 V-0) grade at a thin wall, as most chargers and mains-powered products need.
Polycarbonate (PC) for the most impact strength, clear parts or higher heat.
Polypropylene (PP) for the lowest cost, living hinges (a thin molded strip that flexes as a hinge) and chemical resistance when looks matter less.
ASA for outdoor housings that ABS would yellow.
Glass-filled nylon or PBT for stiff, hot or structural parts.

Three things decide more than the plastic's name: the flame rating your safety standard asks for at your thinnest wall; what will touch the housing, because PC and PC/ABS can crack from cleaning wipes, sunscreen and lotion where the part is under stress; and whether it will sit in the sun.

The price of the resin itself matters less than it seems. In the third quarter of 2026, price-index averages for bulk, general-purpose grades in North America were about $2.09 a kilogram for ABS and $2.36 for polycarbonate, so on a 50-gram housing the difference is under two cents. Flame-retardant, UV-stabilized and pre-colored grades, small orders through a distributor, the mold and the cycle time all matter more than the difference in base resin price.

How do the common enclosure plastics compare?

The table compares nine plastics used for electronics enclosures and their parts: what each does well, where it falls short, how much heat it takes and where it's typically used. The heat column is the heat deflection temperature (HDT), roughly where a loaded bar starts to sag in a short test, here at 1.8 MPa for one example grade from its datasheet; grades within a family differ. HDT isn't a temperature the part can live at for years; for that, use the RTI in the section on outdoors, heat and damp places below.

Plastic	Strengths	Weaknesses	Heat deflection at 1.8 MPa (example grade)	Typical uses
ABS	Tough (high impact resistance), inexpensive, easy to mold, good finish from matte to high gloss, paints well, welds well	Yellows and weakens outdoors unless stabilized; general grades are only slow-burning (HB); can crack with some chemicals under stress; sink marks (shallow dents) over thick areas, and knit lines (faint seams) where flows of plastic meet	About 80 °C	Handheld devices, remotes, computer and phone parts
PC/ABS	Tougher and more heat-resistant than ABS; flame-retardant grades reach V-0 at about 1.2 to 1.5 mm depending on the grade, including halogen-free ones (made without bromine or chlorine flame retardants); costs less than PC	Cracks from disinfectants, sunscreen and lotion under stress; must be dried well before molding, as must ABS, PC, nylon and PBT	About 90 °C	Chargers, appliances, lighting, electronics and telecom housings
Polycarbonate (PC)	The highest impact strength of the common enclosure plastics; clear grades; flame-retardant grades reach V-0 at 1.0 to 1.5 mm depending on the grade	Poor chemical resistance and stress cracking; needs a hot mold and very dry resin; less forgiving of design mistakes; UV needs a stabilized grade	About 130 °C	Phone housings, lenses, light covers, chargers
Polypropylene (PP)	Cheapest; light; resists acids, bases and cleaners; the plastic for living hinges	Floppy; shrinks and warps more; hard to paint or print without surface treatment; needs UV stabilizer; plain grades are brittle at a notch, and flame-retardant grades lose the toughness of impact grades	About 55 °C (unfilled; higher at the lighter 0.45 MPa load or with glass)	Lids, appliance parts, fans, cases with built-in hinges
ASA	Molds and machines like ABS, but holds its color and toughness outdoors	Costs more than ABS; fewer suppliers; some grades are less impact-resistant than ABS, so compare impact data at your coldest use temperature	Similar to ABS	Outdoor housings, heat pumps, signs
Nylon (PA66), glass-filled	Very stiff and strong; high heat; resists oils and solvents	Absorbs water and loses stiffness; warps; glass shows at the surface; wears aluminum molds	About 248 °C (33% glass)	Brackets, frames, clips, gears
PBT, glass-filled	Stiff; high heat; flame-retardant grades reach V-0 under 1 mm; resists oils and many solvents	Warps; poor against acids, bases and some hydrocarbons; costs more	Over 200 °C	Coffee makers, toasters, connectors, appliance housings
Acrylic (PMMA)	The clearest (92% of light through 3 mm); scratch and weather resistant	Brittle; stress cracks; only slow-burning (HB)	About 100 °C	Windows, light pipes, lenses
TPU or TPE (soft)	Soft, grippy and sealing; molded on, TPU bonds to PC, ABS, PC/ABS and PBT, and matching TPE grades bond to PP and nylon	Not structural; TPU won't bond to PP, so use a matching TPE grade or a mechanical interlock	Many grades lose shape above about 80 °C	Grips, bumpers, seals, straps

Some numbers behind the table, all from makers' datasheets: on the notched Izod impact test, a general ABS scores about 320 J/m, a flame-retardant PC/ABS about 530 and a flame-retardant PC about 640, against 16 for acrylic, so PC is roughly forty times tougher than acrylic on that test. Unfilled nylon 66 loses more than half its stiffness once it takes up moisture, from 2,800 to 1,200 MPa in flexural modulus. Common enclosure plastics conduct heat several hundred to a thousand times worse than aluminum, so a plastic housing does little to spread heat away from a hot part.

Does your enclosure need a UL 94 V-0 plastic?

What UL 94 ratings mean. In the UL 94 test, a bar of plastic is held in a flame and timed. HB means it burns slowly when held horizontally. V-0, V-1 and V-2 come from two 10-second flames on a vertical bar: V-0 must go out within 10 seconds and V-1 within 30, neither with flaming drips that ignite cotton below; V-2 has V-1's time limit but may drip burning plastic. 5VA and 5VB use a much bigger flame, 500 W against 50 W for the V tests, applied five times to bars and to a flat plaque; 5VB lets the flame burn a hole through the plaque and 5VA doesn't. They're asked for on large or heavy enclosures.

A rating holds only at a thickness. A plastic is rated at the thickness it was tested at, and thinner walls usually do worse. One flame-retardant ABS is V-1 at 1.0 mm but V-0 at 1.5 mm, so check the rating at your thinnest wall, not the datasheet's best number.

What your product needs. Under UL/IEC 62368-1, the safety standard for most electronics and chargers, whether the housing needs a flame-rated plastic depends on how much power a fault could release, not on what your charger is rated for.

Up to about 15 W (power source class PS1). Circuits that can't deliver more than about 15 W even under a fault are treated as unable to start a fire, and their housing can usually be a slow-burning (HB) plastic. A small lithium cell can push far more than 15 W into a short unless its protection circuit cuts it off, so a battery product charged from a 15 W USB-C port isn't automatically in this class.
15 to 100 W (PS2). Many USB-C and battery-powered products fall here. There's no full fire enclosure, but plastic close to parts that could arc or overheat must be flame-rated or kept away from them.
Above that (PS3). Circuits fed straight from the mains call for a fire enclosure in flame-rated material, typically V-1 or better, which is why chargers and power adapters are usually flame-retardant PC or PC/ABS. Rechargeable lithium batteries also need a fire enclosure under the standard's battery annex, whatever their power class; it can be the battery pack's own case or the product's housing.

Household appliances follow UL/IEC 60335, which uses glow-wire tests near live connections. Ask your safety lab which class applies before you choose the grade; see Which US tests does an electronic product need before you sell it.

Flame retardants cost toughness. In the datasheets, a flame-retardant polypropylene scores 27 J/m on the notched Izod impact test, against 110 to 350 for impact (copolymer) PP, which leaves it no tougher than plain (homopolymer) PP at about 20 to 35; a flame-retardant ABS scores 210 against 320 for a general grade. Use a flame-retardant grade where the standard asks for one, not everywhere.

The safety file names the exact grade. Plastics recognized by UL carry a Yellow Card listing their flame rating by thickness and color and their RTI, the long-term temperature rating. A product's safety listing names the grade it was tested with, so a different grade, a different maker, a color concentrate (pigment pellets the molder mixes into natural resin) or a thinner wall needs the lab's review. Ask whether the color you want is covered, and list approved alternates before the grade you chose runs short.

Which plastics crack from disinfectant wipes, sunscreen and cleaners?

Two groups of plastic behave differently here. Amorphous plastics, which include PC, PC/ABS, ABS and acrylic, can crack when a chemical meets a part under stress, often days or weeks after the chemical first touches it. This is environmental stress cracking (ESC), and common causes on electronics are disinfectant wipes (quaternary ammonium and isopropyl alcohol), sunscreen, hand lotion and some cleaners.

In one resin maker's test at 1% strain, flame-retardant PC/ABS and PC/PET bars didn't survive a common hospital disinfectant, and the blends ranked PC/ABS, then PC/PET, then PC/PBT from least to most resistant. PC/PET and PC/PBT blend polycarbonate with a polyester, which resists chemicals better; they usually cost more than PC/ABS and warp more.
In a 2024 independent lab study, every disinfectant tested cracked PC/ABS held at constant strain within 14 days of twice-daily wiping.
Semi-crystalline plastics, the other group, which include PP, PBT and nylon, generally hold up better to these chemicals.

To lower the risk: pick a chemically resistant grade for products that are wiped often (medical, shared or kitchen devices), keep molded-in stress low with a hot mold and slow cooling, put radii on inside corners and at the edges of holes, and keep snap-fit strain within the maker's limits (for one maker, 4% for PC and 2.5% for PC/ABS on a snap used once, and about 60% of that for snaps opened often). Test with the actual chemicals before the mold is cut.

Which plastic holds up outdoors, in heat or in damp places?

Sunlight. ABS yellows, chalks and turns brittle outdoors unless stabilized; ASA is the outdoor version of ABS. PC needs a UV-stabilized grade or a coating for long outdoor life, and PP needs UV stabilizers or carbon black. A UL "f1" rating on the Yellow Card means the grade passed UL's outdoor tests.
Sun and a flame rating together. If your product needs both, look for a grade whose Yellow Card lists your flame rating at your wall thickness and an f1 outdoor rating. Fewer grades have both, so ask your resin supplier early.
Heat. Check the RTI, the temperature a grade can live at for years, against the hottest spot on your housing: about 60 °C for one general ABS, 85 °C for a flame-retardant PC/ABS and 120 to 130 °C for a flame-retardant PC. Yellow Cards list three RTIs (electrical, mechanical with impact and mechanical without impact); for a housing, use the mechanical-with-impact value, and the electrical one too if the plastic itself insulates live parts.
Moisture. Nylon takes up about 2.6% water at 50% humidity and grows slightly; its stiffness and its electrical properties change with it. Avoid nylon for parts that must hold tight fits in damp places.

How do enclosure plastics differ in molding and assembly?

Shrinkage. Amorphous plastics such as ABS, PC/ABS and PC shrink about 0.4 to 0.8% and evenly; glass-filled nylon and PBT shrink differently along and across the flow, which causes warp. A mold is cut for one plastic's shrinkage, so switching plastics in the same mold can throw dimensions off.
Processing. PC melts hottest, at about 295 to 315 °C, needs a mold at 70 to 95 °C and resin dried to 0.02% moisture; ABS molds at 50 to 70 °C.
Wall thickness. Typical ranges from one molder's guidelines: ABS 1.1 to 3.6 mm, PC 1.0 to 3.8 mm, nylon 0.8 to 2.9 mm and PP 0.6 to 3.8 mm.
Molds. Glass-filled grades wear aluminum molds quickly; see Aluminum or steel injection molds.
Assembly. ABS, PC/ABS and PC weld well ultrasonically with a small molded ridge; PP, nylon and PBT usually need shear joints for a strong or sealed weld, and nylon must be dry. PP is the plastic for living hinges. ABS and PC/ABS paint and plate well; PP needs surface treatment before paint or printing will stick.

Does a plastic enclosure affect Wi-Fi, Bluetooth or cellular antennas?

Plastic lets radio signals through, but a housing close to an antenna still detunes it, so tune the antenna in the final housing, material and wall thickness. Carbon fiber, conductive fillers in static-dissipating grades, metallic paints and heavy carbon black can absorb signals; keep them away from the antenna. Nylon's dielectric properties change as it absorbs water. Plastic gives no EMI shielding on its own; if the product needs shielding to pass FCC emissions tests, it comes from conductive paint or plating on the inside of the housing, or a metal can over the noisy part of the board. For metal housings and antennas, see Sheet metal, aluminum extrusion or CNC.

Example: a housing that gets wiped every day

This is an illustration, not a customer project. The product and all the numbers are made up.

In this made-up case, a tabletop device for clinics runs from a listed external adapter whose output is limited to under 15 W, with only low-voltage circuits inside, and gets wiped with disinfectant several times a day. The made-up first run is 1,000 units, and each housing weighs a made-up 80 g. The safety lab confirms, in this made-up case, that the housing needs no flame rating.

ABS (made-up numbers): at $3.00 a kilogram for the colored grade, $0.24 of resin a housing, $240 for the run.
PC/ABS (made-up numbers): at $4.50 a kilogram, $0.36 a housing, $360 for the run; tougher, but the most prone of the PC blends to crack under the wipes.
PC/PBT (made-up numbers): at $6.00 a kilogram, $0.48 a housing, $480 for the run; resists the wipes better, but warps more, so the design gets more ribs.

Before cutting the mold, the team has a lab hold bars of each plastic bent so their surface is stretched by 1%, under the clinic's wipes for three days, at a made-up $2,000. In this made-up case, ABS and PC/ABS show fine surface cracks (crazing) and PC/PBT doesn't. The mold is cut to PC/PBT's shrinkage. The extra resin costs $240 for the run in this made-up case; if 3% of 1,000 ABS housings had cracked in the first year and each replacement cost $90, the made-up bill would have been $2,700.

The general rule: the difference in resin price is small next to the cost of the wrong plastic, so decide the flame rating and the chemicals first, test before the mold is cut, and then choose the cheapest plastic that passes.

What should you ask your molder or resin supplier?

The exact grade and maker, with its datasheet and UL Yellow Card: the flame rating at your thinnest wall and color, and the RTI.
Whether the color is a pre-colored grade or natural resin with a color concentrate, and whether your safety listing covers it.
The drying, the mold temperature and the shrinkage the mold will be cut to.
Approved alternates if the grade runs short, and whether your safety file lists them.
Chemical resistance data for what your users will put on the housing, and the UV stabilization and outdoor rating.
The minimum order and lead time for that grade and color through a distributor.
For glass-filled grades: the mold steel and how the gates will wear.
RoHS and REACH declarations (EU rules on restricted substances, which many US buyers also ask for), and food-contact or skin-contact documents if your product needs them.

For the design changes from a printed prototype, see Moving from a 3D-printed prototype to injection molding; for sealing the housing, How do you make an electronics enclosure waterproof (IP67) for production?

Where we come in

If you're choosing the plastic for your first molded run, this is one of the situations Anamor takes on. We design each part for the process that will make it, and our quotes list setup costs, such as tooling, separately from unit prices at the quantities you're planning.

Anamor takes US hardware teams with a working prototype into their first production run: we redesign the product for production, line up partner factories and suppliers in the US and overseas, price it at your quantities, and run the build through to shipping.

Send what you have: photos of the prototype, CAD if you have it, how the product is powered, what will touch the housing (cleaners, sun, heat, skin), and how many you plan to make. Need an NDA? We'll send our mutual NDA, or review yours, before you send files. Within two business days, a real person on our team will reply with a free first look at your production run and a few times to talk.

Frequently asked questions

Is ABS or polycarbonate better for an electronics enclosure?

ABS is the usual starting point: it's tough, inexpensive and easy to mold. Polycarbonate is tougher, takes more heat and comes in clear grades, but it cracks more easily from cleaners and lotion under stress and needs a hotter mold. PC/ABS sits between them and is common for chargers that need a flame-retardant grade at a thin wall.

Does a plastic electronics enclosure need to be UL 94 V-0?

Not always. Under UL/IEC 62368-1, it depends on the power a fault could release. Circuits limited to about 15 W even under a fault can usually use a slow-burning (HB) plastic. Mains-powered circuits need a fire enclosure in flame-rated material, typically V-1 or better, and so do rechargeable lithium batteries, though the pack's own case can serve. Ask your safety lab first.

Which enclosure plastics crack from disinfectant wipes?

Amorphous plastics such as PC, PC/ABS, ABS and acrylic can crack where the part is under stress and a chemical touches it, often days or weeks later, and PC/ABS is among the most prone. PC/PBT and PC/PET blends and semi-crystalline plastics such as PP, PBT and nylon generally hold up better. Test with the real wipes before cutting the mold.