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Kako napreduje ovaj moj projekat sa drajverom za lemilice sve više i više ulazim u samu materiju i sagledavam probleme za koje nisam znao ni da postoje. Uvek mi je bilo čudno što moram da setujem lemilicu na 300-350°C da bi nešto zalemio kada se standardna 60/40 kalajna žica topi na 180-190°C. Čak i bezolovne kalajne žice se tope na temperaturama ispod 250°C. Problem je u tome što onog trenutka kada vi krenete da lemite temperatura vrha drastično padne sa temperature na kojoj je bio te kada vi namestite lemilicu da lemite na 350°C lemno mesto ne prelazi 250°C!! Evo ga jedan grafik kako to izgleda na HAKKO lemilici (stara generacija HAKKO936, jedna od najpopularnijih profesionalnih stanica u svetu, i ubedljivo najvise klonirana lemna stanica na svetu, i novija generacija HAKKO FX888, obe lemilice imaju grejač i senzor u dršci dok je vrh obican komad bakra presvucen gvožđem i niklom, osnovna razlike između ove dve lemne stanice je što noviji HAKKO FX888 ima senzor postavljen na drugo mesto).

HAKKO FX888 i HAKKO 936 temperatura pri lemljenju

HAKKO FX888 i HAKKO 936 temperatura pri lemljenju

Ako ne razumete grafikon, evo kratkog objašnjenja. Od 0 do 10sec vidimo crvenu liniju koja je na 350°C. Ta linija predstavlja temperaturu vrha. To nije temperatura vrha koju vidi sama lemna stanica svojim senzorom vec je to prava temperatura vrha merena tako sto je u sam bakarni vrh ugradjen senzor. U desetoj sekundi je vrh dodirnuo prvu lemnu tacku (PCB via) i vidimo kako se manj temperatura lemne tacke sa 25°C do 250°C i kako temperatura vrha pada sa 350°C do 300°C. Zatim smo podigli lemilicu sa te tačke (kada je tačka nakvašena kalajem) i prešli na sledeću i tako zalemili 5 lemnih tačaka. Od osamdesete sekunde vidimo isto to samo sa HAKKO936.
Ono što možemo videti sa ovog grafika je da izmeštanjem senzora u povećanjem snage same lemilice ubrzavamo vreme lemljenja ali i dalje stvarna temperatura vrha mnogo beži od vrednosti nasetovane na samom drajveru (350°C u ovom slučaju).

Rešenje za ovaj problem se nalazi u boljem pozicioniranju senzora. Da bi to uradili, profesionalni lemni sistemi koriste različite sisteme za merenje temperature samog vrha. Od prastarog Weller štosa da u vrh ubaci magnet koji ima određenu kurijevu tacku te tako sam sebe održava na određenoj temperaturi do novih vrhova koji više nisu “glupi komad bakra” već se grejanje i merenje prebacuje iz drške u sam vrh. Ako pogledamo profesionalnu klasu HAKKO lemnih stanica, npr. HAKKO FX951 videćemo da se u dršci više ne nalazi “ništa”. Drška je u ovom slučaju bukvalno to – drška, ona ima na sebi kabl i prihvatač za vrh. Vrh u ovom slučaju više nije glupi komad bakra već u sebi sadrži i temperaturni senzor i sam grejač tako da pri proizvodnji vrha senzor može da se smesti u sam vrh, ne postoji problem kontakta između senzora i vrha a grejač opet može da bude adekvatne snage (ne kao do sada isti grejač za sve vrhove) i da bude koncentrisan “gde treba”. Ovakav vrh je naravno malo skuplji od “glupog bakarnog” ali, ne znam kako, proizvođači su uspeli da zadrže cenu vrlo realnom. Prosečan kvalitetni “glupi” vrh košta oko $5 dok prosečan “pametni” vrh (tip cartridge) košta oko $12. Ako uzmemo u obzir da kada zamenite vrh zamenili ste i senzor i grejač, to je vrlo prihvatljiva cena (samo još da su i same lemne stanice prihvatljive).

Ima mnogo proizvođača pametnih lemilica, ja dosta spominjem HAKKO (japanski brend, veoma kvalitetan možda u svetu najrasprostranjeniji, najvise kloniran…) iz razloga što ja imam jedan original i jedan klon i sa njihovim programom sam najbolje upoznat. Uz njih sam krenuo da pravim ovaj moj drajver kako bih probao programski da rešim mehanički problem izmeštenog senzora. Da probam da prepoznam kada je krenulo lemljenje i na vreme krenem da grejem vrh…. Kako mi za taj drajver treba sprava koja radi to što hoću da izvedem kako bi mogao da uporedim rezultate, a i pošto mi treba još jedna dobra lemilica rešio sam da se obradujem sa novom spravom i uzmem sebi jednu lemnu stanicu koja trosi ove pametne vrhove. Rešio sam u startu da izbegnem Evropske proizvođače (Ersa i ekipa) pošto su malo nenormalni sa cenama i finalna odluka je pala između HAKKO FX951 i PACE ST50 stanica. Japanski HAKKO je cca 30% jeftiniji i ima odličnu podršku ali PACE ima patentirane microwave vrhove koje HAKKO ne sme da prodaje u Evropi i Americi tako da ja ne mogu da dođem do njih…. Za razliku od HAKKO-a, PACE u Srbiji ima i regularnog zastupnika, momci su vrlo spremni da pomognu i savetom i na svaki drugi način, imaju servis. Uz sve to PACE vrhovi su i nešto jeftiniji od HAKKO vrhova tako da sam finalno odlučio da uzmem PACE ST50. Naravno uzeo sam ga u USA pošto je cena ipak dosta niža nego kada se na nju doda Srpska carina, transport, marža, pdv, porez na srpstvo, porez na Kosovo, porez na SPC, porez na to što kupujes spravu skuplju od 10$, porez što si ostao u Srbiji, porez što si glasao …

Da ne dužim, sprava izgleda ovako:

PACE ST50

PACE ST50

 

Ništa spektakularno, aluminijumski profil, prednja maska ima on/off prekidač, jednu ledaru, 3 dugmeta i led displej sa 3 sedmosegmentna “karaktera”. Ima sa strane mesto da se za samu bazu pričvrsti držač za dršku, nosač za policu, držač za vrhove … Pozadi ima šteker (onaj standardni “kompjuterski” tropinski) za 230VAC i ima šteker za “instant set-back caddy”.

Unutra je isto vrlo jednostavna. Kvalitet izrade je očigledan. Jedan torus za napajanje, sve uredno, PCB sa prednje strane, dvostran, populisan sa obe strane. MCU koji tera celu spravu je NXP P87C51RB+4A, dakle klasican OTP ’51. Cela sprava interno radi na 5V.

PACE ST50 skinut zadnji poklopac

PACE ST50 skinut zadnji poklopac

 

PACE ST50 skinut prednji poklopac

PACE ST50 skinut prednji poklopac

 

PACE ST50 PCB

PACE ST50 PCB

PACE ST50 pcb1

PACE ST50 pcb

PACE ST50 weird capacitor

PACE ST50 weird capacitor

Šta je ovaj kondenzator – nemam pojma, tj. vidim da je 6800uF ali je malo povelik za 6800uF 10V (cela plocka je na 5V znaci ne treba mu više), piše 50WV .. pretpostavljam da je to 50V mada ne kontam sta predstavlja ono W (ovo W je “Working Voltage”, imam ja drugare koji znaju kada ja ne znam :D ) … a dodatno me cudi cemu služi 50V ovoliki kond. Izgleda da on tuče DC u grejač a ne AC. Na gornjoj slici vidimo 10 tranzistora ili sta su već ( 7XMN / 4A06 ) na ulazu gde dolazi AC napajanje ..

Konektor sa zadnje strane sprave ima 3 pina: 5V, GND i još jedan. Taj jedan je pull up-ovan na 5V koliko sam ja izmerio i vezan je direkt na mcu na pin 5 (P1.3/CEX0). Ja sam probao da ga spustim na GND i ništa se nije desilo, tako da pretpostavljam da po tom pinu ide nesto više od on-off već da piči neki 1wire ili tako nešto.

Elem, obzirom na ovaj veliki kondenzator i precizni 0.050000R shunt na ploči, kao i odsustvo triaka pretpostavljam da lemilica definitivno tuče PWM-om DC u grejač.

Neke interesantne osobine

  • Vrhovi koštaju 10-15$ zavisi od vrha do vrha. Vrhovi postoje u dve osnovne verzije i to su “obični” vrhovi koji imaju gvožđe pa nikl preko bakra i “dijamantski” koji preko bakra imaju poseban sloj gvožđa koji je filovan dijamantskom prašinom. Fora sa ovom dijamantskom prašinom je da su vrhovi mnogo izdržljiviji nego kada preko bakra ide čisto gvožđe
  • PACE ima čuvene vrhove sa “udubljenjem” koji služe za lemljenje smd čipova. To udubljenje pomaže u čišćenju viška kalaja sa pinova i olakšavaju / ubrzavaju lemljenje višestruko. Ovu vrstu vrhova je patentirao PACE i u USA i Evropi tu vrstu vrhova pored njih sme da prodaje samo Weller pošto su platili PACE-u prava za korištenje. Ovi vrhovi su jedan od osnovnih razloga što sam se ja odlučio za PACE a ne za HAKKO
  • PACE ST50E (E je od Europe, tj 230V verzija) koristi IntelliHeat tehnologiju te na nju mogu da se okače 2 vrste drški. TD-100 drška za koju sam se ja odlučio koristi ove “pametne vrho0ve” dok PS90 koristi “obične glupe vrhove”. Pored klasičnih drški na ovu stanicu može da se okači i pinceta TT65 ili MT100. Sve drške i pincete imaju varijantu sa i bez azotne sredine za lemljenje
  • Auto SetBack opcija ove lemne stanice se aktivira ako za neko predefinisano vreme (bira se iz menija od 10 do 90 minuta) niste koristili lemilicu ona spušta temperaturu lemilice na 175°C kako bi produžila radni vek vrha. Iz ovog moda izlazite tako što stisnete crveni taster. Svaki put kada koristite lemilicu brojač za auto setback se resetuje i ta detekcija da li lemilicu koristite ili ne radi zastrasujuce dobro
  • Auto gašenje lemne stanice. Ako ste neko predefinisano vreme (bira se iz menija 10 do 90 minuta) ostavili lemilicu u setback modu lemilica ce se ugasiti. Odlična opcija za nas koji često ostavimo lemilicu da “nešto završimo” i onda se vratimo kući posle 3 dana
  • Menjanje vrhova na živo. Svi proizvođači lemnih stanica govore kako je bitno koristiti odgovarajući vrh za odgovarajući lem. Za lemljenje nekog TQFP-a ili MSSOP-a treba da se dohvatite MicroWave vrha ali ako lemite 0603 otpornik onda vam treba neki mini chisel a kada treba zalemiti trough hole konektor onda neki konus ili veći chisel tip rešava problem. Sa standardnim glupim vrhovima ovo znači da ili imate nekoliko štapova pa ih menjate, ili lemite prvo sve što vam treba sa jednim vrhom, sačekate da se ohladi, zamenite ga, pa lemite sa drugim .. Ono što TD-100 drška daje kao mogućnost je 2sec izmena vrha. Uz štap dolazi i posebna silikonska “traka” kojom lepo uhvatite vruć vrh, izvadite iz štapa, ostavite na tome predviđeno mesto na držaču drške, i zabodete u dršku novi vrh, sve to na živo i sve za 2sec

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gb


As mine Soldering Iron Driver project progress I’m getting more and more acquainted with the matters surrounding it and I’m finding solutions to the problems I never had idea existed. I always found it strange that I have to set temperature on my soldering iron to 300-350°C in order to get something soldered when regular 60/40 soldering wire melts at 180-190°C. Even lead free soldering wire melts below 250°C. The problem is that when you start soldering, the moment you touch the solder point with your tip, the tip temperature start to drop dramatically. Because of that when you set your tip temperature to 350°C soldering pojnt will never go over 250°C!! Here’s a graph from HAKKO (old generation HAKKO936, one of the most popular soldering stations in the world and definitely the most cloned station out there, and the HAKKO FX888, soldering station designed more recently; both irons use hand piece that holds both sensor and heater while tip is a “dumb” piece of copper coated with iron and nickel. Major difference between the two is that HAKKO FX888 has a sensor that’s positioned differently compared to old 936).

HAKKO FX888 i HAKKO 936 temperatura pri lemljenju

HAKKO FX888 i HAKKO 936 temperatura pri lemljenju

If you have problem understanding the graph, here’s the short explanation. From 0 to 10sec we see a red line sitting around 350°C. That line represents the tip temperature. That is not the tip temperature sensed by the soldering driver but a tip temperature measured by a special sensor embedded directly into tip (for sake of this test). In the tenth second the tip touched soldering point (PCB VIA) and you see how temperature of the soldering point goes from 25°C to 250°C while tip temperature drops from 350°C to 300°C. Then we move tip from this point to the next one (after the first point was wet with solder) and repeat this for all 5 soldering points. From the 80second mark we see the same process but with HAKKO936.

What we can see on this graph is that moving the sensor to “better position” and with slight increase in power of the soldering iron we increase the soldering time but the temperature of tip still differs significantly from the temperature we set our driver to maintain.

Solution for this is to better position the temperature sensor. In order to do so professional soldering systems use different solutions to measure tip temperature; from prehistoric tip Weller used to put a magnet with specific Currie point into tip and regulate temperature with magnetic switch responding to the tip up to the tip cartridges that are no longer “dumb pieces of copper” but sophisticated pieces of hardware. This way we move both heater and the sensor in the tip. If we look at HAKKO professional class, for e.g. HAKKO FX951 we’ll find that hand piece is stupid piece of plastic with few wires only while tip in this case instead of being stupid piece of copper gets everything done (sense the temperature, heats .. ). This way we do not have the the contact resistance between sensor in handle and the tip, the tip can be properly placed, the heater can be properly dimensioned (so for tip with different heat capacity you can have different heater). The tip cartridge is, of course, bit more expensive then the regular dumb tip but to mine surprise the price difference is not high. While dumb tips are in the $5 range the tip cartridges are in the $12 range and that’s not nearly as expensive as one might expect. Taking into account that every time you replace tip you replace the heater and sensor, this is very acceptable price (only if the stations themselves are as affordable :( )

There is a number of soldering station manufacturers; I mention HAKKO a lot (Japanese brand, high quality, very popular, one of the mostly cloned brands in the World..) because I have one original HAKKO and one clone hence I know HAKKO better then others. I started my Soldering Iron Driver with my HAKKO station in order to try to solve in software what high end stations solve in hardware. The idea is to sense when you start to solder and to push enough power into iron to keep the temperature high. Since I had to be able to compare my SID with the professional stations, and since I need one more iron, I had to get me one of these soldering stations that use tip cartridges. I decided to avoid European manufacturers (Ersa and co) as they have abnormal prices hence I ended up deciding between HAKKO FX951 and PACE ST50E with TD-100 handpiece (E is just 230V version). Japanese HAKKO is 30% cheaper but locally I don’t have a service for it while PACE have a local representative and on top of all that PACE hase patented microwave (miniwave too) tips that are killers for smd soldering. On top of that PACE tips are bit cheaper then ones for HAKKO I ended up with PACE.

This is how the station looks like:

PACE ST50

PACE ST50

 

Nothing spectacular, aluminium profile, front mask with on/off switch, led, 3 buttons and a 3 digit 7seg display. There’s a grove in the profile to attach caddy, rack holder, tip holder .. On the back there’s standard 3pin power connector for 230VAC and a connector for “instant set-back caddy”. What I noticed is that transformer has a single input hence ST50E version for 230VAC and ST50 version for 110VAC have different transformer!! It is not just a matter of reattaching a wire to move from 230 to 110 and vice versa, so be sure to order the one you need!!

Inside everything is very simple; manufacturing quality is excellent and obvious. Very neat, single thyroidal transformer with multiple outputs, PCB in front, double sided, populated on both sides. MCU running the station is NXP P87C51RB+4A, so classic OTP ’51. The whole PCB runs on 5V.

PACE ST50 skinut zadnji poklopac

PACE ST50 skinut zadnji poklopac

 

PACE ST50 skinut prednji poklopac

PACE ST50 skinut prednji poklopac

 

PACE ST50 PCB

PACE ST50 PCB

PACE ST50 pcb1

PACE ST50 pcb

PACE ST50 weird capacitor

PACE ST50 weird capacitor

I’m not sure what’s the reason for this big capacitor. I see that it’s 6800uF but 50WV is bit uncommon for me. I read that WV means “working voltage”. It seems that this station push DC into the heater, probably trough 10 of these fet’s in parallel: 7XMN / 4A06, and the big capacitor is used to smooth out the PWM as it probably measures current in order to determine temperature. It makes sense taking into account also the 0.05000R shunt on board :)

The instant set-back caddy connector is 3pin one, 5V, GND and “unknown”. The “unknown” pin is pull-up to 5V and is linked directly to mcu pin 5 (P1.3/CEX0). I tried to lower it to GND but nothing happened so I assume something other then just a switch is on that pin, maybe some 1wire or something similar.

Some interesting facts

  • Tips cost $10-$15 depending on the tip type. Tips come in 2 major groups, the “normal” ones that have iron and then nickle over the copper and the “diamond” ones that has the iron layer infused with real diamonds. This significantly increases tip longevity (or so they say)
  • PACE patented famous miniwave tips with “dimple” / “pool” that are used for smd chips. This “dimple” sucks the solder from the pins so no bridges are formed and soldering of fine pitch components is made very easy. PACE patented this tips and besides them only Weller sells this type of tips in EU and USA (I assume Weller paid royalty or something to PACE). Hakko has this type of tips but they sell then only in Asia so this was one of the reasons I went with PACE and not with HAKKO
  • PACE ST50E (E is “Europe”, 230V version) uses IntelliHeat technology so you can attach any IntelliHeat hand piece to it. Major 2 types of handpieces are TD-100 hand piece that I decided to go with (uses the cartridges) and PS90 hand piece (that uses dumb copper tips). You can also attach tweezers TT65 or MT100. All hand pieces and tweezers exist in version with nitro soldering env.
  • Auto SetBack option activates if for a predefined time you do not use your soldering iron. When you do not use iron for predefined time the iron temperature will be dropped to 175°C in order to increase tip life. You exit this mode by pressing red button or by just using your iron. This works surprisingly well
  • Auto power off option kicks in if for predefined time your station spends in auto setback mode. This is invaluable option for us boys who tend to leave soldering iron on and “run to finish something” returning 3-4 days later finding iron still running.
  • You can change tip while iron is working and while they are hot :). Every soldering equipment manufacturer will say how using proper tip size & shape for a solder joint is important. Of course we all usually select a tip that will fit “most” the board we are working on because changing tips is lengthy process. You normally need to wait for iron to cool off before you switch tip – NOT ANY MORE :D, with TD-100 you just take the tip with provided rubber mat, take it out of the hand piece and place on the tip holder on the caddy, get a new tip and click it in place – voila, you changed the tip in under 2 seconds :D

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