production needs us · 2020-02-27 · selective soldering systems. the dimensions in this document...

Production needs us

Layout Recommendations for Selective Soldering Systems

ERSA VERSAFLOW , ECOSELECT , ECOCELL and SMARTFLOW

© by Ersa GmbH| VF3_LAYOUT ENG_V503.pptx | 23.05.2017

General

The present document is based on long-term experience of users and shows standard situations. Special cases are not considered. Larger distances as

shown in this document are always possible.

The component clearances above and below the assembly depend on constructive circumstances and also on available options of the single systems

(e.g. center support, component hold down systems, etc.)

The clearances given in this document show the standard situation in the selective soldering systems. The dimensions in this document for Miniwave

soldering are based on a solder nozzle diameter of 6 mm. The range of Solder nozzles diameters is 4.5 – 32 mm

If there are any uncertainties please contact Ersa GmbH.


Layout recommendation for selective soldering systems with Miniwave soldering units


VERSAFLOW / ECOSELECT / ECOCELL / SMARTFLOW

Maximum PCB or Mask Dimension

Width

Direction of

transport

Length

If the leading edge of the PCB is chamfered, the chamfer should not exceed 1,5 x 45°

When the chamfer exceed 1,5x45° the stoppers in the machine have to be modified.This will affect the component clearance at the board edges.

The minimum and maximum dimensions of the assemblies, which can be processed in theappropriate selective soldering systems, are to be taken from the technical specification data sheets.The max. PCB or carrier thickness at the edge of the conveyor is 6mm.


Keep out areas conveyor system VERSAFLOW / ECOSELECT / ECOCELL

Distance of the components to the edge of the PCB (top) side

Component height* max. 120 mm

Distance from edge min. 4 mm

Board/mask thickness max. 6 mm**

Direction of transport

BE height is measured from the bottom side of the board

Distance from edge

*

** at the conveyoredge sidesPlease see page 6

*There is a max. component height of 80 mm for SMARTFLOW and ECOCELL


Keep out areas conveyor system VERSAFLOW / ECOSELECT / ECOCELL / SMARTFLOW

Distance of the components from the edge of the PCB on bottom side and their maximum height.

The max. height of the components

decreases in adjacent areas of the

selective soldering joints.

Please see page 15.

Max. component height 30 mm

Exceptions to 60 mm are possible.

Please contact Ersa in this case.

Scrap edge min. 3 mm5 mm are possible!

Please see the specification of the system


Required keep out area around a selective solder joint and distance to adjacent SMT

components / smallest solder nozzles

The required keep out area around a selective solder joint depends on:

1. dimension of the solder nozzle

2. distance to adjacent SMT components

The decision of which solder nozzle to use, depends on the keep out area around the selective solder joint. For

designing new layouts the minimum dimensions of the solder nozzles, as shown in the following pages,

should always be considered !

The dimensions of the smallest solder nozzle is Ø 6mm.*

To these dimension of the outer nozzle body, a safety area for the flowing solder has to be added, to avoid wetting of

adjacent components or conveyor systems. The sketches on the following pages will show the different situations.

With the single solder nozzle of the Versaflow two possible soldering methods can be used:

1. single point soldering (single solder joint)

2. track soldering (connectors etc….)

* Smaller solder nozzles on request.




Schematic diagram of soldering - and restricted areas

THT Solder joint

Area of soldering

Restricted area for non

selective solder joints

Area of soldering: Area which is wetted by the solder wave. It is quite possible that the real solder joint might be

smaller. The position of the solder joint within the area of soldering could be choosed. If possible a

symmetrical/central position should be strived.

Restricted area: Within this area there should be no adjacent components which are not going to be selective

soldered.

Important: Highest priority is the integrity of the restricted areas. If their size is less than specified, adjacent

SMD components may be spilled away during the selective soldering process.



Keep out area around a single solder joint / minimum condition

X1

X

Minimum diameter of the restricted area X1 is 5 mm.

Minimum distance X of the area of soldering to the next

SMD pads is 1.5 mm.

Target condition of the solder joint is the central position

within the area of soldering.

THT-Solder joint

Area of soldering



For smaller distances, contact ERSA !



Explanation - Keep out area around a single solder joint / area of soldering

Minimum condition:

• diameter of the restricted area (yellow) is 5 mm

• diameter of the area of soldering (blue) calculated: 5 mm – (1.5+1.5 mm) = 2 mm

• Diameter of the pads (red) e.g. 1.2 mm

If the pad is smaller than the area of soldering then the solder joint can be positioned within the solder area freely.

The central position within the area of soldering is to be aimed.



Keep out area around single row – multiple pin solder joints / minimum conditions

Minimum width of restricted area X is 6 mm.

Length of restricted area Y depends on pin count of

the component.

Minimum distance X1 of the soldering area to the

next SMD pads is 2 mm.

Minimum distance Y1 of the soldering area to the

next SMD pads is 2 mm.

Target condition is the central position of the solder

joint within the area of soldering.



Area of soldering

THT Solder joint



Keep out area around multi row – multiple pin solder joints / minimum conditions / pitch > 2 mm



Area of soldering

THT Solder joint

Minimum width of restricted area X is 6 mm

Length of restricted area Y depends on pin count of the

component.

Minimum distance X1 of the soldering area to the next SMD

pads is 1 mm.

Minimum distance Y1 of the soldering area to the next SMD

pads is 3 mm, better is the half of the width of the soldering

area.

Target condition is the central position of the solder joint

within the area of soldering.For smaller distances, contact ERSA !



Keep out area around single row – multiple pin solder joints / minimum conditions / pitch > 2 mm

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Keep out area around the conveyor edge / minimum conditions

All restricted areas may touch the conveyor clearance B.

Specification of the conveyor clearance B. see page 6

For smaller keep out areas please contact Ersa!



Component height at the solder side of the PCB around the selective solder joint

The maximum component height X on the solder side is 30 mm (page 6).

Directly around the solder nozzle and the nitrogen guide, the the component height X is limited

For dimension of the nitrogen guide see page 16

*If you need higher components on the solder side please contact ERSA!



Clearance around solder nozzle 6 - 14 mm

The clearance is rotation-symmetrical.



Thermal impact area around the solder nozzle

The exhausting nitrogen, which forms the protective atmosphere for the solder process, leads to a higher thermal

load of components in the area around the solder wave.

Depending on the mass of the components temperatures > 130°C can be easily reached.


Layout recommendation for selective dip soldering with Multiwave soldering units


Clearances for all dip soldering systems with multiwave

Maximum PCB or Mask Dimension

Width

Direction of

transport

Length

If the leading edge of the PCB is chamfered, the chamfer should not exceed 1,5 x 45°

When the chamfer exceed 1,5x45° the stoppers in the machine have to be modified.This will affect the component clearance at the board edges.

The minimum and maximum dimensions of the assemblies, which can be processed in theappropriate selective soldering systems, are to be taken from the technical specification data sheets.The max. PCB or carrier thickness at the edge of the conveyor is 6mm.


Component height* max. 80 mm

Distance from edge min. 4 mm

Board/mask thickness** max. 6 mm

Direction of transport

Component height is measured from the bottom side of the board

Distance from edge


*

Distance of the components to the edge of the PCB (top) side

** at the conveyoredge sidesPlease see page 21


Max. component height 25 mm*


* The max. component height on the solder side

of the PCB depend on several factors. Therefore

it can deviate from 25 mm.

In case of doubt please contact Ersa.

Distance of the components from the edge of the PCB on bottom side and their maximum height.

Scrap edge min. 3 mm5 mm are possible!

Please see the specification of the system


General Requirements to Selective Solder Joints

Wire/Lead Clinches

It is important to pay close attention when bending (clinching) the wire/lead, that the bent portion of the lead

does NOT extend past the outer limit of the TH pad. If this, however, must be the case, please contact ERSA

for approval.

target condition contact Ersa

The clinch angle β is a non-critical factor for soldering



Required keep out area around a selective solder joint and distance to adjacent SMT

components / smallest solder nozzles

The required keep out area around a selective solder joint depends on:

1. dimension of the solder nozzle

2. distance to adjacent SMT components

The decision of which solder nozzle to use, depends on the keep out area around the selective solder joint. For

designing new layouts the minimum dimensions of the solder nozzles, as shown in the following pages,

should always be considered !

To these dimension of the outer nozzle body, a safety area for the flowing solder has to be added, to avoid wetting of

adjacent components or conveyor systems. The sketches on the following pages will show the different situations.



Schematic diagram of soldering - and restricted areas

THT Solder joint

Area of soldering



Area of soldering: Area which is wetted by the solder wave. It is quite possible that the real solder joint might be

smaller. The position of the solder joint within the area of soldering could be choosed. If possible a

symmetrical/central position should be strived.

Restricted area: Within this area there should be no adjacent components which are not going to be selective

soldered.

Important: Highest priority is the integrity of the restricted areas. If their size is less than specified, adjacent

SMD components may be spilled away during the selective soldering process.



Keep out area around a single solder joint / minimum condition

THT Solder joint

Area of soldering




Minimum distance X of the area of soldering

to the next SMD pads is 3 mm.

Minimum diameter of the restricted area Y

is 10 mm.

The smallest solder area is Ø 4mm.

Target condition is the central position of the

solder joint within the area of soldering.



Explanation - Keep out area around a single solder joint / area of soldering

Minimum condition:

• Diameter of the restricted area (yellow) is 10 mm

• Diameter of the area of soldering (blue) calculated: 10 mm – (3+3 mm) = 4 mm

• Diameter of the pads (red) e.g. 1.5 mm

If the pad is smaller than the area of soldering, the solder joint can be positioned within the solder area freely. The

central position within the area of soldering is to be aimed.



Keep out area around multiple pin solder joints / minimum conditions

THT Solder joint

Area of soldering




The minimum size of the restricted area

X x Y is 10 x 10 mm².

The min. distance X1/Y1 of the area of soldering to adjacent

SMT pads is 3 mm

The smallest solder area is 4x4 mm². The position of the

solder joint within the area of soldering is not relevant.

With multiple row components the measure X is to be raised

by the grid measure.

The measure Y depend on the length of the connector.

The schematic can be applied for single and multiple row components



Keep out area around multipolar soldering / minimum requirement for non-wettable nozzles with

drain holes (Ersa – standard)


X

X1Y

Y1

The component height X1 within close proximity of the

solder nozzle is 4.5 mm and depend on the position Y

of the drain hole.

The standard measure of Y is 7.5 mm, in special

cases, to be modified.

The min. distance Y1 is from the nozzle to the next

component without height restriction is 15 mm.


The schematic can be applied for single and multiple row components



Keep out area around the transport edge / minimum conditions

For smaller keep out areas please contact Ersa!

All restricted areas may touch the conveyor clearance B.

Specification of the conveyor clearance B. see page 21


Not Adjustable support pins on the nozzle plate

The diameter of the restricted area on the PCB is 4-8 mm, it depends on the height of the adjacent components. See dimensional drawing.Supporting pins may be required to compensate for possible bending or warpage of the assembly during soldering when e.g. tends by heavy components and / or due to their size to sag.The restricted areas for these pins should be distributed as possible in a uniform , square - symmetrical grid , depending on weight and size of the PCB.


Special shapes possible on request.


Adjustable support pins on the nozzle plate (for custom pallets or solder masks)

The diameter of the restricded area on the

circuit board is 10 mm.

Supporting pins may be required to compensate for possible bending or warpage of the assembly during soldering when

e.g. tends by heavy components and / or due to their size to sag.

The restricted areas for these pins should be distributed as possible in a uniform , square - symmetrical grid , depending

on weight and size of the PCB.



General Layout Recommendations for

Selective Soldering


Use of custom pallets / solder masks

By the using of custom pallets/solder masks is to be paid attention to the fact that the level of the conveyor

system is identical with the level of the soldering side of the assembly.

Divergences only make sense in special cases. Please match with ERSA.

Conveyor level A = PCB bottom side B +/- 0,05 mm

PCB rest thickness C 2 mm

General recommendations

custom pallet


Use of custom pallets / solder masks

The edges of the pallet, which show into the direction of transport should show a chamfer. The chamfer should

not to be chosen too largely otherwise the position of the pallet for soldering, when hitting the board stop, may

move by the chamfer and may cause an offset for the soldering process.

Chamfer max. 1,5 x 45° Radius max. R1,5

General layout recommendations


Orientation of adjacent SMT components to selective solder joints

Tangential Orientation

Parallel Orientation brings the disadvantage

that in case of a wetting of the reflow

soldered SMT component, the component is

washed away immediately.

Radial Orientation

In-line Orientation is much better, as the wetting

of the reflow soldered pad is improbable and the

component will not be washed away so easily.

General layout recommendations


General Layout Recommendations

Layout for connectors

short Pins small pads large pads wrong ground connection

Long pins

Conclusion:

Layout impacts

on Quality !



Capillary Effect during Selective Soldering / Ratio of Pin- Hole Diameter

capillary gap

To increase the transfer of heat into the plated through-hole, it is recommended to work on the upper limit of

the capillary gap at PCBs/components with large heat capacities.

The heat up gradient of the solder joint is a function of the solder volume in the gap of the plated through hole.



Thermal relieve/heat trap for connecting a PTH to a massive copper layer

The „spoke design“ reduce the heat flow into the copper layer, therefore more of the available heat can remain in

the metallization of the through hole. This geometry is recommended on the primary and secondary side of the

board as well as for internal copper layers.

The longer and narrower the spokes are, the more effective for soldering they will be.



Thermal relieves in power electronic assemblies



The impact of massive components

If components guard the solder joints against the effect from top

side heating's, all the necessary heat energy must be supplied

for the heat up of the solder joints exclusively from below.

To guarantee a quick heat up of the solder joint, heat energy is

transferred to the top side of the assembly by additional vias

around the PTH.



Through Hole Filling

FhG ISIT

The wrong PCB design (missing “spokes”) on the left picture causes a insufficient through filling.

The insufficient through filling on the right picture is caused by the heavy mass component.


General Requirements to Selective Solder Joints

Mechanical connections and fixations in components/ snap-ins

Very often connectors are equipped with plastic pins for additional mechanical fixation to the PCB. If the

board locks may not come in contact with molten solder, they have to be treated like SMT components, and

the same layout-specs have to be applied.

Keep out area not ok Keep out area ok


production needs us · 2020-02-27 · selective soldering systems. the dimensions in this document...

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