PCB Board FR-4, 2 copper planes vs. Plastic POM/Acetal

Compare PCB Board FR-4, 2 copper planes vs. Plastic POM/Acetal strength, stiffness, weight and thermal properties.

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PCB Board FR-4, 2 copper planesComposite

Plastic POM/AcetalBulk polymer (molded or machined)

Mechanical
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Yield strength	not given (tensile used)	69MPasourcetypical (single ASTM D638 tensile strength)
Ultimate tensile strength	246–385MPasourcethe bare laminate's (fr4-370hr), in-plane: cross direction .. length direction (ASTM D3039)	69MPasourcetypical
Compressive strength	not sourced	124MPasourcecompressive stress at 10% deformation
Flexural strength	not sourced	99MPasourceflexural yield strength, typical
Elongation at break	not sourced	75%sourcetypical
Young's modulus (stiffness)	21.9–25.8GPasourcethe bare laminate's (fr4-370hr), in-plane: cross direction .. length direction (ASTM D790-15e2); the copper planes are left out	2.8GPasourcetypical
Density	not sourced	1,420kg/m³sourcetypical (DuPont product information for Delrin 100 NC010; 'The data listed here fall within the normal range of product properties')
Strength to weight	not sourced	48.6kN·m/kg
Stiffness to weight	not sourced	1.97MN·m/kg
Poisson's ratio	0.171–0.177sourcethe bare laminate's (fr4-370hr), in-plane: cross direction .. length direction	0.35sourcetypical
Shear modulus	10.2GPa9.8x stiffer in shear	1.04GPa
Bulk modulus	12.2GPa	3.11GPa
Speed of sound	not sourced	1,404m/s
Thermal
Thermal conductivity	not sourced	0.4W/m·Ksourcetypical
Thermal expansion	13–14µm/m·Ksourcethe bare laminate's (fr4-370hr), in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C)	122µm/m·Ksourcemean, 29 to 60 °C
100 mm part over a 50 °C swing	67.5µm growth9.04x less	610µm growth
Specific heat	not sourced	1,465J/kg·Ksourceaverage -18 to 100 °C, Delrin acetal resins (not grade-specific)
Heats up and cools (diffusivity)	not sourced	0.192mm²/s
Thermal shock resistance	not sourced	52.5W/m
Melting point	not sourced	175°Csourcecrystalline melting point
Max service temperature	not sourced	125°CsourceHDT 1.8 MPa (annealed)
Values for	A whole circuit board read as one orthotropic plate: the JEDEC high-K thermal test board (JESD51-7, "2s2p"), 0.062 in (1.575 mm) thick with two internal solid copper planes 0.0014 in (1 oz) thick, as Texas Instruments SZZA017A Table 1 gives it. Copper C110 and the Isola 370HR laminate from this library; the layers conduct in parallel along the board and in series through it (boardStackup.ts). Its two 0.0028 in trace layers cover little of the board and are left out; vias are ignored. Mechanical values are the bare laminate's.	DuPont Delrin 100 acetal homopolymer, Table 2 'Typical Properties of Delrin Acetal Resins' (ASTM methods), Delrin Design Guide Module III hosted on delrin.com

Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Is PCB Board FR-4, 2 copper planes stronger than Plastic POM/Acetal?

PCB Board FR-4, 2 copper planes is stronger: its tensile strength is 315 MPa against yield strength 69 MPa for Plastic POM/Acetal (4.57x).

Which is stiffer, PCB Board FR-4, 2 copper planes or Plastic POM/Acetal?

PCB Board FR-4, 2 copper planes is stiffer: Young's modulus 23.9 GPa against 2.8 GPa for Plastic POM/Acetal, so the same part in PCB Board FR-4, 2 copper planes deflects less under the same load.

Which expands less with temperature?

PCB Board FR-4, 2 copper planes expands less: 13.5 µm/m·K against 122 µm/m·K for Plastic POM/Acetal.

Among 73 materials

Stiffness against density

Strength against density