BGA Rework Station T862++ Comments on design

[Fraser]

I have now got my hands on a T862++ BGA IR rework Station for working on small BGA chips.

Looking at the spare IR lamps I see that they are somewhat expensive for what they are. The lamps are either 12V 100W or 15V 150W depending upon what specification you read. The lamp is a MR16 format 50mm diameter with full reflector (not Dichroic !) whilst the supplied lamp has a gold colour reflector, an aluminium reflector should work fine so I do not think the gold is essential for operation (just marketing ?). A dichroic reflector is unsuitable as it allows most IR energy to escape to the rear of the lamp. Solid aluminium layer reflectors used for ceiling light fixtures project the IR energy forwards which is what we need for IR Rework.

Has anyone with a similar lamp driven IR source head tried using a common (and much cheaper at £6) 12V 100W MR16 Halogen lamp in place of the supplied lamp.

These BGA rework stations are, without doubt, the bottom end of the IR Rework Stations but such does not mean they are without their uses. He more expensive IR6000 uses a 400W ceramic IR source in its head and this costs only £6 for the ceramic heater or £60 for a complete head assembly. If the T862++ needs improvements I shall likely install a head based on the IR6000 design and ceramic heater. A relatively simple project.

I could not justify the expense of a full blown expensive IR Rework station my needs are relatively humble. This is just adding IR Rework to my various hot air Rework stations. I managed to buy the new T862++ unit At an excellent price. If it proves deficient in its role it will be improved or sold on. Sometimes you have to try something yourself to determine whether it is adequate, or not. I have plenty of scrap laptop PCB's etc to test it on

For info, the official lamps cost from £22 to £50 ! depending upon source. With an average life of only 300 hours that is a consumable running cost that needs to be considered. Even the IR6000 is vulnerable to killing its ceramic heater if the thermocouple temperature sensor moves out of the heating zone ..... it fries its own heater and likely anything in the beam in the process ! At least the T862++ lamp does not have that issue but it can still fry components if used incorrectly.

I would be interested to hear others personal experiences of the budget T862++ but please do not make assumptions about its performance from others experiences without having tested it yourself. User error is a common cause of issues with even the simplest of Rework technologies 

Fraser

[Fraser]

OK, comments on the T862++ after some research into its operating principle and the embodiment of such in the unit under discussion

1. The operating principle of using a combination of powerful IR emitting lamp and collimating lens(es) is a proven solution to BGA and SMD soldering and desoldering.

2. The incorporation of specific lenses to suit IC dimensions is both desirable and effective in providing a controlled thermal field and so avoid unnescessary thermal shock or heating to surrounding components.

3. The IR lamps used to generate the Infrared energy are 'tuned' for maximum IR output rather than visible light wavelengths. Their use for this application is both justified and wise so using a common 12V 100W Non dichroic reflector Halogen lamp may still work, but is not an optimised solution.

3. The T862++ incorporates a 600W ceramic 120mm x 120mm lower pre-heating plate. This is considered adequate for the intended use and IC dimensions. The pre-heating of the PCB carrying the IC is very important but pre-heating of the whole PCB is not essential provided care is taken with the localised pre-heating stages. Expansion stresses and thermal shock to components within and outside the are of pre-heating area must be considered.

4. The IR lamp on the T862++ is controlled by a 'PID' in the base unit. The design of the lamp controller is too simple for the intended task and appears to operate much li,e a Microwave oven controller that it injects energy into the target are by simple on/off cycling of the heating source. Such a simple approach may suit heating food but it is far from optimal for heating a delicate IC and PCB. The correct approach would be far more analogue in nature and the IR Lamp PID should provide a PWM output to drive the IR lamp at a level appropriate to both gradually achieve the target temperature on the IC, and maintain it for the required period of time. Further control in the form of a programmable stepped heating and cooling cycle further
Enhances performance. A K type thermocouple should be used to provide the PID with an accurate surface temperature of the IC or PCB. Non contact IR K type thermocouple sensors may be used to further enhance the design. Programmable PWM PID's are now common and relatively inexpensive. Many provide PC control capabilities.


So in summary, the T862++ is a sound mechanical design that uses a proven approach to heating BGA and SMD technology. Its flaws lie in the control of the IR energy source and the IC/PCB temperature monitoring, in fact it provides no such temperature measurement. The unit is clearly 'entry level' and sadly it will easily destroy components if not used with intelligence and care. The on/off cycling of the IR lamp rather than a PWM drive to gently increase and decrease its output is a serious flaw in my opinion. The lamp life is reduced by on/off cycling and thermal shock is induced into the component being illuminated in the IR energy beam. The physical build of the u it appears more tha. Adequate for the basis of a good BGA Rework station working with the smaller BGA IC's. I suspect that PC North and South Bridge IC's dimensions would be the limit of the units capabilities, even after improvements are made to the design.

Am I happy with my purchase ? Yes. Thee are more expensive u its that claim greater performance but those are also lacking in some areas. The IR6000 is an example. It uses a ~400W 80mm x 80mm ceramic IR radiating plate as its IR above decks heat source. Thee is no collimation of the thermal energy leaving that heat source beyond the head casings shape around the ceramic heater. The design appears flawed in this respect but could likely be improved without too much effort.

I will be sourcing a PWM programmable PID for my T862++ and may already have one in stock. As I paid far less than the normal retail price for the T862++ I do not begrudge this small extra expenditure or work as it will make the unit fa.r more useable and will also extend the life of the IR lamp. At £23 each that is a good idea.

Some may wonder why I have made no mention of the soldering iron supplied with the T862++. The reason is that it is the standard cheap and nasty soldering iron available as a soldering station at very low cost. It's performance is relatively poor and it is not well thought of by many users. I do do not intend to even connect it to the base unit. A decent quality soldering iron is highly recommended for any serious electronics work on BGA or fine pitch SMD pins.

Finally, in its ex factory form. The T862++ may work as an IC removal and installation system, but it will easily cook the IC and components that reside within its powerful IR beam. I have watched I. Horror as some You Tube videos show people virtually incinerating BGA chips and PCB's with this unit. All tools should be used with intelligence !

Fraser

[Fraser]

The PID that I will likely use for controlling the IR lamp will be the 'D' version of an Altec PC410 that has multiple step processes that may be programmed into it. This unit is a favourite for DIY IR BGA stations and Ovens. There are multiple output versions including Relay, Logic and analogue voltage or current.

Fraser

[Fraser]

Doing a bit of study on Halogen lamp feeding and care. I had forgotten about the importance of maintaining the envelope at 250C for the Halogen effect that prolongs the lamps life. Inrush current is the enemy that I must tame. The manufacturer of the T862++ may have already covered that issue in the design, but if not, I will look to address it with a modification. Likely a NTC in series with the lamp. I will also abort my original idea of variable drive to the lamp as only a 10% drop in rated voltage is considered safe for lamp life. It looks like I am stuck with the lamp cycling on/off mode of operation.

Fraser

[blacksheeplogic]

I have no experience with IR so this is an interesting thread and I hope you expand on it further, I would not have though that the control was just a simple on/off cycle but I guess it worked good enough for the price point.

The problem with the hot air rework station I have is the cost of the nozzles, they are several hundred dollars each.

[Fraser]

This will be my first experience of IR soldering and desoldering so it is a learning curve for me.

With regard to the control of the IR lamp, I will investigate it further when I receive the unit. From videos on You Tube the lamp appears to be switching on and off with the 'on' duration changing with the temperature setting. There is no monitoring of the true temperature on the IC or PCB in the IR beam. I am expecting a pretty crude system for driving the pre-heater and IR lamp. I have found a 'teardown' video of the base unit and it looks to be very much built down to a price on the electronics front. There is definitely room for improvement and even upgrades. My unit cost me £127 delivered which is about as much as I want to spend on this model.



Fraser

[j395]

Has anyone with a similar lamp driven IR source head tried using a common (and much cheaper at £6) 12V 100W MR16 Halogen lamp in place of the supplied lamp

try to connect several bulbs without reflectors - 3x3 - 3 in series, 3 groups in parallel.
I used 1..2kW 190/254mm linear lamps for bottom pcb heater (3..4 in series to reduce visible light emission) - worked great, heating much faster than ceramic heaters, so temperature regulation is better. One drawback - eyes blinding after long work, so better use quartz tubes with nichrome wire

[Fraser]

Well the T862 arrived today after much delay thanks to DHL issues !

OK, in summary, these units are best described as 'form over function'. They look 'right' read 'right' in the specs, but are far from a good design 

So what have I found that I do not like ?

1. The unit arrived and is the older 'single lens' lower spec model and not the one shown or described in the auction. This is a seller issue though and I think I will be returning the unit to him.

2. The fan has become detached from the head in transit .... not great build quality !

3. Screws were heard rattling around inside the base unit and fell out of the air vents ..... not a good start !

4. The 'lens' that is fitted can only illuminate a 20mm x 20mm BGA chip .... pretty useless really.

5. The supplied 'lens' is NOT an optical collimator, it is a glass windowed 'mask' ! It contains no lens elements of any form. A quality solution contains at least two collimation lens elements and a diffuser plate to improve the Delta T across the output beam.

I can likely improve the unit and if it were the correct T862++ model instead of the inferior old T862, I might be motivated to do so, but looking at this inferior T862 I do not feel very motivated at the moment !

Not a great day, but no one died eh 

Fraser

[Fraser]

The seller of the unit has been really honourable and accepted a return without issue.

I also discovered that the gold plating on the IR lamp was sloughing off ! Oh dear 

This T862 is heading back asap.

I would advise careful research and thought before buying any of the T862 versions, even if they are relatively cheap. As I said.... form over function and the absence of ANY collimating optics beyond the lamp reflector geometry leaves this design severily wanting. It imitates more expensive professional IR lamp based units but only in the use of an IR lamp and its external appearance !

One to avoid

Fraser

[Fraser]

Well this story has taken a change of direction......

The seller of the unit is a really personable chap. We discussed the units failings and we agreed to my keeping the unit with a very large partial refund from him as much work is needed to make the unit functional for BGA format IC's. I now have a decent casing and the core components needed for an IR Rework station.

I intend to do some experimentation with this unit and address its shortcomings. High on the list is the poor optical design of the head. I intend to fit at least one lens element to create the concentrated and better formed IR heating beam needed for BGA IC reworking. Relying on just the lamps reflector is far from optimal. I already have a large are IR pre- heater and will likely extend the head support pole to enable me to use the pre-heateron top of the units deck. This will provide greatly improved pre-heating when dealing within larger chips and PCB's.

I may still investigate ways of reducing the lamps high output to reduce scorching effects, but that will need some thought.

Fraser

[Fraser]

I am now kicking myself for binning all my LCD projectors as they would have been a great source of optical components ! That is the problem with having a clear-out, you often bin useful stuff as well as junk 

In a arc lamp LCD or DLP projector you will find clever optics that even out the illumination from the lamp before it passes through the collimator lens(es). It is these components that might be useful in a IR Lamp based BGA station as the lamp is similar in optical design. Time to start hunting in the attic maybe, I may have missed the odd dead LCD projector somewhere

I also have several Meopta Photographic enlargers that I purchased just for their baseboard and excellent head support pole design. The optics are large and likely not optimal for IR Rework though. Some experimentation is needed.

For experiments I will likely use just a standard cheap visible light reflector lamp to assess the beam shaping characteristics of a particular lens. I can save the IR Lamp for later when performance tests using a thermal camera are carried out.

Note.... the UI lamps used in these workstations have a life of only thirty hours ! That is one tenth the normal life of a similar wattage visible light Halogen reflector lamp ! At almost £25 per lamp that is almost £1 per hour of use. Eeeek ! Fortunately BGA Rework with IR lamps tends to use short 'lamp on' times. I may well fit an NTC initial current surge limiter in series with the lamp to extend its life a little though. Soft starting the filament is kinder to it than snapping it on and off as I think the design currently does.

Fraser

[Chris56000]

Hi!

My employer bought us one of these for surface–mount and small BGA rework, and so far we've not had any issues with it – I've been three years at my present job and it was bought before I started work here!

(Rantings from my friend to get his Z80 pcbs designed and made mean I've not had a chance to investigate mine yet, but when I can get to it circuit diagrams'll be drawn out!)

Chris Williams

[Fraser]

Hi Chris,

That is both interesting and good news 

Looking at the designs of professional IR lamp based units costing many thousands of Pounds, I feared the unit I have is just a very poor, and likely ineffective, cheap clone.

From my research the issues with these cheap 'entry level' units seem to be poor preheating, uneven heating of the BGA IC and no thermal profiling at all. Some users sadly also cook the IC's through poor usage of the equipment.

I am hopeful that I can make the unit an effective tool with only minor modifications. The lack of any optics in the head is the reason for the less than even heating across large BGA IC's and the high power of the IR source can scorch the PCB or IC if care is not taken. Like many tools, some skill is needed to use them effectively, but if the tool is fatally flawed, no amount of skill can compensate for such. The T862 is not without hope though  If I can do some decent BGA rework for the £70 I paid for the unit I will be happy 

I certainly have enough thermal cameras to analyze the "above deck" heating head behavior and improve it where required   

Fraser

[Chris56000]

Hi!

Further to my previous note, I replaced two L6205PD motor power driver chips, (which are the type with a back surface intended to be soldered to the PCB groundplane for earthing/heatsinking purposes), on a very desely packed layout weighing machine PCB at work last Thursday with no blistering or damage to the PCB substrate whatsoever using my employer's tool!

The way I did it was to apply plenty of liquid flux to the PCB surface and the back surface of the L6205PD device, solder the device's normal pins to the PCB pads as usual, add more flux around the chip, then return the PCB under the IR lamp, letting it cycle on and off until the solder on the pins and the groundplane starts to flow, then allow not more than 2 on/off cycles of the lamp, then switch off and remove the PCB.

Subsequent examination, both by myself and a colleague showed the new devices were quite satisfactorily soldered to the PCB (unfortunately I didn't take pics but if the PCB comes back I will!)

I think the lamp setting we use is about 260° and the lamp housing is about 4–5" (100–120 mm) above the PCB and components being soldered, and I always switch off and remove the PCB being worked on as soon as the solder on the device being removed melts enough to allow the old device to be flipped off the PCB.

Chris Williams

[iabarry]

Oct 2019 - Just got a T-862.  This version is preconfigured for 110v and US plug. 
On the 2nd use, the On/Off switch for the IR broke. I tore into it and used the switch for the soldier iron for now. New switches of the same size are available from Digikey.

Using the smallest "lens" (really just an orifice), I am down to about 2" from the lens to the IC. I have a separate TC and display touching the PCB adjacent to the part of interest and can watch the temp closely.

Being really close allows the IC temp to go up quickly from ~180C to 225C as this is the portion of the curve that needs the rapid transition. If you have the IR heater higher, it will take a lot longer. Likely this is a temp ~=  1/(distance^2) relationship, so distance matters. The youtube videos show people taking FOREVER to heat the part. This is not about making soup or stew. Look at the solder time/temp curves and you'll see that you can't take many minutes at the top of the curve.

If you're using a T-862, please post some comments.
Thanks