Design Guidelines: Overmoulding & Insert Moulding

Our basic guidelines for overmoulding and insert moulding include important design considerations to help improve part manufacturability, enhance cosmetic appearance, and reduce overall production time.

We offer a number of secondary moulds and tooling services to support your project.


Size

Maximum Dimensions

SIZE

203mm x 406mm x 152mm

VOLUME

966,837mm³ 

DEPTH

72mm from parting line

Up to 203mm if the parting line can pass through the middle of the part

Projected Mould Area

112,903 mm² (plastic)

30,968 mm² (silicone rubber)

 

Height may be limited if using a silicone as the overmould material, and deeper parts are limited to a smaller outline. Minimum part volume is 40 mm² Smaller if side-actions are required

With substrate moulds, we can maintain a machining tolerance of ±0.08mm with an included resin tolerance that can be greater but no less than 0.005mm/mm.

With thermoplastic overmoulds, tolerances remain the same as substrate moulds, however, if the overmould is LSR, then tolerances shift to 0.06mm.


Design Feedback

For additional questions, please contact an application engineers at customerservice@protolabs.co.uk or
+44 (0) 1952 683047.


Insert Moulding Capabilities

Instead of a mould that produces a final part using two separate shots like overmoulding, insert moulding generally consists of a preformed part—often metal—that is loaded into a mould, where it is then overmoulded with plastic to create a part with improved functional or mechanical properties.

One way insert moulding is used is with threaded inserts, which reinforce the mechanical properties of plastic parts’ ability to be fastened together, especially over repeated assembly. Bushings and sleeves are another great way to increase part durability for mating components that need more abrasion resistance due to moving parts


Materials

  • ABS
  • Acetal
  • HDPE
  • LCP
  • PEI
  • PMMA
  • Polycarbonate
  • Polypropylene
  • PPA

 

  • PPS
  • PS
  • PS
  • PSU
  • TPE
  • TPU
  • PEEK
  • Liquid Silicone Rubber

 

 

VIEW MATERIALS >


Overmoulding Material Bonding

Chemical bonding between overmoulded materials is possible, but material compatibility should be considered in order to achieve desired bond strength. Incorporation of an adequate mechanical bond is strongly recommended if bonding is critical to your application. An undercut is a good example of a mechanical bond.

 

Substrate Material
Overmould
Material
ABS
Polylac PA-717C
ABS/PC
Bayblend T65 XF
PC
Makrolon 2458
PBT
Celanex 2002-2
PP
Moplen RP348R
Nylon 66
Zytel 70G30HSLR
TPU
Pearlthane 11T85
C C C C M M
TPV
Sarlink 3170
101-87
M M M M C M
TPE
Thermolast K TC6 MLZ
101-64
M M M M C M
LSR - Elastosil
3003/30 A/B
- - M M - M
TPC
Hytrel 4068FG
C C C C M M

M = mechanical bond recommended

C = chemical bond


Surface Finishes

 

FINISH DESCRIPTION
PM-F0 non-cosmetic, default
PM-F1 low-cosmetic, most toolmarks removed
SPI-C1 600 grit stone, 10-12 Ra
PM-T1 SPI-C1 + light bead blast
PM-T2 SPI-C1 + medium bead blast
SPI-B1 600 grit paper, 2-3 Ra
SPI-A2 grade #2 diamond buff, 1-2 Ra

 


Draft

VERTICAL FACES 0.5°
MOST SITUATIONS
MINIMUM FOR SHUT OFF
MINIMUM FOR LIGHT TEXTURE (PM-T1)
MINIMUM FOR LIGHT TEXTURE (PM-T2) 5°+

 


Undercuts

Maximum Side Core Dimensions

WIDTH HEIGHT FULL
<213.84mm <60.38mm <73.66mm



Wall Thickness

MATERIAL

RECOMMENDED WALL THICKNESS
ABS 1.143mm - 3.556mm
Acetal 0.762mm - 3.048mm
Acrylic 0.635mm - 12.7mm
Liquid Crystal Polymer 0.762mm - 3.048mm
Long-Fiber Reinforced Plastics 1.905mm - 25.4mm
Nylon 0.762mm - 2.921mm
Polycarbonate 1.1016mm - 3.81mm
Polyester 0.635mm - 3.175mm
Polyethylene 0.0762mm - 5.08mm
Polyphenylene Sulfide 0.508mm - 4.572mm
Polypropylene 0.635mm - 3.81mm
Polystynene 0.89mm - 3.81mm
Polyurethane 2.032mm - 19.05mm

* The table is adapted from manufacturingcenter.com.



Radii

Some part corners will have a radius rather than a sharp edge since we use an automated CNC milling process to make the mould for your parts. This typically does not require a change to your model, but resulting radii are identified before the mould is milled.


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