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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


through hole reflow

#21795

through hole reflow | 1 October, 2002

We are looking at possible doing a few through hole components on the smt line. Is this feasable? What types of components are diffucult to do this way? What stencil considerations are there? Anyone have any info on this subject?

reply »

#21796

through hole reflow | 1 October, 2002

No problem. A standard stencil is OK. You want to print a half moon shape on each side of the hole. Make sure you print about X2 the size of your hole and make sure you keep the print in close to the hole. You want to print X2 the hole size as to have enough to fill the hole with out voids.

reply »

#21797

through hole reflow | 1 October, 2002

Q1: Is this [paste in hole] feasible? A1: Yes, many people lower their operating cost by reflowing through hole components.

Q2: What types of components are difficult to do this way [paste in hole]? A2: Types of through hole components that are difficult to reflow solder are: * Those that cannot bear the heat of the reflow oven. * Connectors whose pitch is so fine that there is not enough room to lay-down enough paste to get adequate hole fill.

Q3: What stencil considerations are there [in paste in hole]? A3: Primary consideration is printing enough paste to get adequate hole fill. Paste is 90% metal by weight and 50% metal by volume.

Q4: Anyone have any info on this subject [paste in hole]? A4: There are boatloads of information on the subject. Start by searching the fine SMTnet Archives.

reply »

Stephen

#21799

through hole reflow | 1 October, 2002

You have to be sure the TH parts can take the reflow temps. A lot of time you willl have to get special components. We do some BNC's this way, but they had to be special order BNC's. There is more info in the fine SMTnet archives.

reply »

Bob Willis

#21821

through hole reflow | 3 October, 2002

SMTNet has a video tape and interactive CD ROM on Intrusive Reflow Soldering that you may want to check out.

In addition there are some free inspection standards for pin in hole printing, placement and soldering available at http://www.dpmo-monitoring.com They were produced for a project as IPC does not currently cover the requirements of this process.

Bob Willis

reply »

#21833

through hole reflow | 4 October, 2002

Hi Barry,

One consideration that you may want to consider is the lead to hole ratio. The higher the ratio, the less solder is required to fill in the gaps and give you a fillet.

Heat is a concern. You will need to ensure components will take the heat of reflow.

Real estate for the solder paste will be a concern.

We have used this method in several applications and have extremely good luck.

Hope this helps.

Good Luck

Christopher Lampron

reply »

Reflow Oven

reflow oven profiler