A CHEAP XRAY machine to align BGA circuits

bga soldering machine

Last year i built a soldering machine for BGAs .. kinda very primitive but it WORKS (sometimes ) IF i can perfectly POSITION MY BGA parts ..So my dream was to BUILD a XRAY machine .. .A friend whose father was a retired DENTIST offered me to DONATE me his FATHER OLD equipment .!.. well i'm still waiting .!
Last night i DISCOVERED this SCIENTIFIC AMERICAN project .. that appears to be SIMPLE ..if you can find one of those ealry TUBES or MAKE IT ..

**broken link removed**

I found on the WEB several places where i could get one of those TUBES ..but
i can probably make ONE! ..

vacuum pump for wirebond machine

If you are going to make one of these, do not forget the lead shielding. X-rays can be lethal in cumulative doses. You should also make a timer so you can walk away from the machine before it turns on.

hobby x-ray machine

In fact this is quite intresting idea. I think you shoud try whit some kind CCD camera, to obtain dynamic picture at the time of alligment. May be first step, shoud be testing CCD matrix, for X ray sensitivity. If it works, exposure will be smaller than in conventional way, i.e. more safe for you. Xray is no just fun, in my opinion...
Can you describe in some detail your way of soldering BGA?
Thanks in advance!

bga machin

i was looking to make some bga solder machine too can you put your project or te theory to do that ???
thx alot ..

bga solder machine

It was a very productive night .. last night i have a good grasp now on what is involved ..i know now how to vaporise magnesium ,i even found a site that explains how to do the glass work .The equipment is not very expensive ..
The only remaining item is where to get a "good&cheap" vacum pump ..
But i have a lot to do first to gain the kind of skills needed to do the glass work ..!
I'm thinking that the HIGH voltage could be obtained with a TV flayback circuit ..
I don't intent to do a big tube ..but a small one like a flash light ..!

To the last person .. I posted some time ago a link to the german BGA soldering project ..
search ...search is here ..
you need to tranlate it to english though ..!!

bga circuits

You are going to need at least 50kV for penetrating a BGA and up to 1mA of current. Most TV flyback only produce up to 30kV. I previously worked at an x-ray tube company here in the US. You can use a CCD camera but you need some material to coat the lens so that when x-rays hit it, it illuminates the material. You can find some inexpensive Image Intensifiers and some tubes on eBay, but you need to find one with a small enough focal spot to get any descent resolution.

bga x ray machine

Moss said:

In fact this is quite intresting idea. I think you shoud try whit some kind CCD camera, to obtain dynamic picture at the time of alligment. May be first step, shoud be testing CCD matrix, for X ray sensitivity. If it works, exposure will be smaller than in conventional way, i.e. more safe for you. Xray is no just fun, in my opinion...
Can you describe in some detail your way of soldering BGA?
Thanks in advance!

Click to expand...

using X-Rays to position the bga chip is not a good idea, open X-ray source is harmfull and cause cancer,the people,s who take X-ray wear a kind of protective colth which bolck the X-ray to effect on body i have seen such tool which used to alling the BGA chips on board before soldring, based on IR based CCD Camera such device can be found on any electronic store which have biult in IR CDD better to make that kind of tool with CCD

further more every PCB maker can make four stop on four corner to help out to aling the BGA

xray pcb machine

Most placement equipment uses fiducials manufactured into the board to locate the proper position for BGA components.

Fiducials are surface copper dots made next to opposing corners of the BGA, and at board extremities, when the circuit board is laid out. The alignment is to the visible dot instead of trying to look through the BGA package.

Fiducials are explained with pictures at the following url:
https://www.tkb-4u.com/articles/other/fiducial/fiducial.php

For such alignment, a camera is used to position the placement head by targeting the dots. This technique is simpler, cheaper, and safer than xray positioning

You risk eye damage, impotence, and cancer messing with xray as an amatuer. An electron with enough energy to penetrate a BGA package has engough energy to penetrate your body to a damaging depth. Much of the damage is cumulative with exposure.

cheap bga placement machine

What is the cost of Machine ?

how to align bga ic

Hi,
As House_Cat already mentioned, assembly shops do not use X-Ray to test for proper alignment. They use X-Ray only to try to diagnose problems on failing boards after reflow.
Having studied some X-Ray pictures of boards, they are not that revealing. The image and detail is not that clear.
You also need very good focus control to be looking right at the solder interface level. If you are too high you will be seeing the wire bonds in the IC. If you are too low, you are under the BGA pads on the PCB.
As another solution to BGA registration, consider this. Most parts have protection diodes on the I/O pins to both the power and ground rails. If you can get access to an IO pin of three of the four corners of the part, then assuming that your solder paste is conductive prior to reflow, you can use a diode check to insure the proper alignment. Since I am assuming you are doing your own board layout and design, you can build this feature into the board.

Another possibility is alignment pins in the PCB. Again, assuming that you can dictate the PCB layout, you can place large via holes at the edges of the package and then place pins in these holes temporarily to guide you in placing the BGA. After reflow, just push out these mechanical alignment pins.