Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Interested in pin-in-paste process with standard ROHS connectors

Views: 21001

#88149

Interested in pin-in-paste process with standard ROHS connectors | 29 June, 2022

Hi. Alpha metals recently informed us of:

Alpha OM-565

low temp solder which they note is popular with pin-in-paste process of through hole parts so that we can solder inside of our SMT oven (1809EXL).

We commonly use ROHS DSUB connectors (9 to 78 pins) for our PCBAs.

Any comments on if such (standard) through hole connectors can support the 175 peak temp required to melt this solder paste ?

We will source a jar and attempt to use but ideally prefer to use our existing ROHS inventory of through hole parts but without deforming the connectors.

Thanks.

Attachments:

reply »

#88150

Interested in pin-in-paste process with standard ROHS connectors | 29 June, 2022

I don't know about that paste, but I can give my experience trying intrusive reflow (pin in paste).

Using standard Lead-Free paste, we often had issues. It seems that many ROHS parts can't actually handle reflow ROHS temperatures. So the fact that you are looking to low temp is already one in the plus column. Another issue we've had is just getting enough paste down to fill the barrel and get a proper joint. Over printing might be necessary, or perhaps the use of solder preforms. I have had to utilize a few tricks when trying to include pin-in-paste on a 4-mil stencil to increase paste at the TH locations only.

Good luck

reply »

#88152

Interested in pin-in-paste process with standard ROHS connectors | 30 June, 2022

Thanks. Yes, we have attempted to use standard ROHS profiles in the past and turned our THT connectors into 'chucky dolls' after the PCBA left the oven.

We then realized that we need the high temp nylon connectors to allow for the use inside the SMT oven. However, such parts are not worth the expense.

Our local rep for Alpha is sampling us this latest solder paste for testing. Will update this thread once we have received and tested against our parts.

reply »

#88153

Interested in pin-in-paste process with standard ROHS connectors | 30 June, 2022

I have used Bi based solder pastes before. What I can say about them is that they are brittle. Joints were cracking easily. This product is something new on the market, so it might be better. Keep in mind to test it for dropping and vibration and joint strength - they say in their website that it performs better than "other low temp alloys". Please share what you get as results - we are very interested to hear. Don't forget, that RoHS connector doesn't necessarily mean its body can withstand reflow temperatures.

reply »

#88169

Interested in pin-in-paste process with standard ROHS connectors | 6 July, 2022

No experience with low temp solders for PIHR but we do use standard lead free 245-255 peak profiles on high temp connectors frequently. Honestly the added cost of the high temp connector pays for itself in labor.

I almost always use oversized apertures on the stencils to get a good amount of solder deposited into the barrel. Nothing special, 4 mil stencil single pass and good barrel fill with a nice fillet on both sides.

One of the other big concerns should be stickout of the through hole leads. I have found that 20-40 mil on the through hole side gives the best results.

reply »

#88170

Interested in pin-in-paste process with standard ROHS connectors | 6 July, 2022

Also I should mention, I've ditched the formulas for getting the "optimal" solder amount after being bit by them once. Now I just design a PCB with 4-10 spots for the connector then order a stencil with a range of aperture sizes. Figure out what gives the best balance between solder balling and barrel fill/ fillet size

reply »

Reflow Oven

Global manufacturing solutions provider