1. LDS Antenna DESIGN GUIDELINE
External
update

2. DOCUMENT OVERVIEW Design Guideline contents
Description of the technology
Process description
Material selection
Design rules
3D data
Plastic part
LDS over moulding
Structuring
Recommended gate locations & types
Metallisation
Design Guideline / LDS Antenna
27/04/2017
18/06/2010

3. DESCRIPTION OF THE TECHNOLOGY
LDS (Laser Direct Structuring) is a technology used to add an antenna radiator or circuit pattern directly onto a plastic carrier.
The technology can be used on free form surfaces, i.e. 3D
A special LDS type plastic resin is needed.
Selected surface areas are activated by laser. The activated areas will then be selectively plated in an Electroless plating process.
Design Guideline / LDS Antenna
27/04/2017
18/06/2010

4. PROCESS DESCRIPTION Injection Moulding Laser Processing Metallization
Design Guideline / LDS Antenna
27/04/2017
18/06/2010

5. MATERIAL SELECTION Suitable materials for stand alone antenna modules
PC/ABS DSM Xantar LDS 3710 (black)
PC/ABS LNP Thermocomp NX07354P (black)
PC/ABS DSM Xantar C RC 3711 (Grey colour) for improved plateability
Suitable material for housing and frame components
PC/ABS DSM Xantar LDS 3720 (black), improved impact strength
List of available LDS materials
NOTE! Materials marked yellow in list and
mentioned above tested at LOM
Design Guideline / LDS Antenna
27/04/2017
18/06/2010

6. DESIGN RULES
a. 3D data
The data used for programming is STP-file including the solid plastic carrier and surfaces showing the antenna pattern. The antenna pattern surface shall be on cero distance from plastic surface. It is crucial that the 3D data is corresponding to the real plastic part.
The plastic carrier is not corresponding to the 3D data. Cut in laser structuring
due to wrong 3D data or mistake in tooling.
3D data shows rounded corners.
Design Guideline / LDS Antenna
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27/04/2017 6

7. DESIGN RULES b. Plastic part:
Sharp-edged transitions should be avoided in laser structured areas to be metallized. Recommended edge radius: min 0,15 mm.
While designing interlayer connections, the following design rules for one-side or two-side conic layout of the interlayer connections must be considered. Other dimensions can be used but needs to be investigated in each case. Please contact LOM ESI.
Design Guideline / LDS Antenna
27/04/2017
18/06/2010

8. DESIGN RULES b. Plastic part:
Avoid tool parting in plated areas if possible. In case of plating over parting is necessary, extra care must be taken designing the tool to get good tool parting. No burrs or parting step acceptable. Problems can cause a gap in structured area
Design Guideline / LDS Antenna
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9. DESIGN RULES C A B b. Plastic part
Ejector pins are not allowed on plated area.
The part surface roughness should be less then Rz 5 µm.
Plastic part should have well defined reference surfaces for all axes, X Y and Z. To get good repeatability in laser structuring the part needs good guiding in the LDS jig. A: Round hole with tight tolerance that guides in X and Y B: Oblong hole to guide in Y (rotation) C: Flat surface, rib, to support in Z.
Other types of guiding can be used but needs careful investigation. C A B
Design Guideline / LDS Antenna
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10. DESIGN RULES c. LDS over moulding Before over moulding
In case of over moulding of antenna pattern extra attention must be taken for optimum results
Guiding and fixing of antenna carrier in tool.
To be able to place the carrier in the tool, guiding holes are needed. If possible use same that was used for LDS jig.
To fixate part before moulding, some part of the carrier must be pressed down by the tool. Areas used for fixating can not be structured. Fixating and guiding must be carefully reviewed with tooling and part designer.
Support. When over moulding, high pressure will push the carrier towards the tool support surface. If there are gaps, such as recess from ejector pin or marking surface, this surface will be deformed. All areas with plating must have perfect support.
Before over moulding
Recess from ejector pin
After over moulding
Over moulding material.
Carrier is compressed plating cracks.
Design Guideline / LDS Antenna
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11. DESIGN RULES d. Structuring
Recommended conductor path width: >0,15 mm
Recommended conductor path distance: >0,20 mm
Conductor lines should be designed so, that they are not too close against walls. In this way a possible sedimentation of ablation products i.e. foreign deposition at the wall is reduced. The steeper the angle of the inclination, the longer the distance should be kept. 0,15 mm with 45° wall inclination 0,25 mm with 70° wall inclination
Design Guideline / LDS Antenna
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12. RECOMMENDED GATE LOCATIONS & TYPES
Hot runner cramping system should be selected instead of rod cramps or belt cramps if possible, because otherwise often unwanted foreign metallization can emerge by mechanical activation of plastic at the breaking edges or shear traps.
Avoid placing gate at or too close to antenna radiator. Rough surface for gate can cause insufficient structuring and cause skip plating. If OK plated, plating still very rough.
Avoid weld lines in antenna radiator areas
Design Guideline / LDS Antenna
27/04/2017
18/06/2010

13. DESIGN RULES FOR METALLISATION
Lots of small pockets will increase solution drag out and thus increase chemical consumption as well as contamination of following baths
Try to avoid surfaces with pockets on more than one side
If pocket on two sides cannot be avoided, design a through hole so that solution can easily run through
Metallisation available
Electroless Copper
Electroless Nickel
Immersion Gold and Electrolytic Gold on request
Avoid small pockets
Design Guideline / LDS Antenna
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