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Brief review of the Zhengbang ZB2520HL reflow oven (T-962A alternative)

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Hi everyone, i recently acquired a ZB2520HL and wanted to give a brief review since there is not too much information out there.

Purchase and shipping
The only source for the unit seems to be buying it directly from the manufacturer. I haven't seen any resellers yet. I purchased it through their Aliexpress store. For six days, shipping status did not change, almost hitting the 7-day refund period from Aliexpress. When it was shipped on day six, things went really fast. It took FedEx less than a week to ship it to Germany and bring it to my doorstep. The unit came extremely well packed, as it should, as it weighs in at 19kg. A really sturdy 15mm thick cardboard box, wrapped in 20 layers of plastic. The unit itself was nested in custom styrofoam pieces and wrapped in a plastic bag. No complaints there, I've seen worse shipping from R&S.  :-+

The oven comes wit a power chord, a serial cable, 1,5m of aluminium flex tube for the exhaust, and a brief english manual. You can tell that was not translated by a native speaker, but is significantly better than the traditional "chinglish" manual we see with a lot chinese products. No worries there.

The unit is built very well. Chassis is earthed, although the earting does not extend to the one thing you are guaranteed to touch: the drawer. That sits on two rails with some plastic parts, mounted in separate shafts to precent it from heating up. My guess is that the plastic coasters prevent the earthing. The drawer grip is separated by a couple of fibre board washers to prevent it heating up. It does get warm, but not too warm to touch.
Some cosmetic issues with my unit: The front decal was loose in a corner. The drawer has some sputter from the laser cutting. The entire drawer is covered by a fibre glass sheet, so the PCB does not sit on the metal. I'm guessing this aids even heating, as the IR now does not reflect off the shiny drawer surface, but is converted to heated air. The cooling fan for the control unit is always on one you power the unit, and it is rather loud.
The oven has an internal fan that spreads the hot air around. So far, I've not been able to find any cold spot in the drawer, it seems to work well all the way into the corners. The unit does not emit any bad smells, all materials seem to hold up to the temperature, not like the T962, that tries to kill everyone in the room by vaporizing some shoddy masking tape.
Overall, the build quality is very good for the price class. You get a really solid unit, powder coated all around and the construction is solid as a rock. The exhaust fan is made of metal to withstand the temperature of the expelled air.

The unit comes with four preinstalled temperature profiles, with profiles 3 and 4 for unleaded  soldering. It is advertised as a 1,6kW unit, and the power analyzer reports 1628 Watts when the  unit is heating. So the power is spot on  :-+
Peaking through the double glass window, we see four IR heaters and a fan.
I ran a couple of test boards with both leaded and unleaded paste. The leaded out-of-the-box profile seemed a litte too cold for the paste. I don't have a thermocouple available to check the temperature, so I'm not sure whether that's the paste or the ovens fault. The unleaded profiles all worked very well. JST connectors stayed white and did not melt. the soldering was perfect with the exception of some balling which I attribute to myself not baking the boards beforehand. The oven does have a fixed temperature mode that allow you to prebake components and boards to drive the moisture out. The power seems ample for an oven of this size, but i haven't run any huge boards through it yet. I will update this review as information becomes available.
The menu is a bit wonky. It has a lot of unnecessary button presses, and when the text is scrolling, the buttons do nothing, which is mildly annoying.
I did not test the software yet, mainly due to the fact that the interface is RS232. An USB or Ethernet connection would be a nice upgrade, although  RS232 does have the advantage of longer cable lengths over USB. (EDIT: The software was not supplied by ZB and there seems to be no download available)

The ZB2530HL is a decent oven for hobbyist or even small professional labs on a budget. While not without flaws, considering the price point of €385 + taxes, you get a lot of (zheng-)bang for your buck. Aliexpress actually deducted the Chinese VAT due to the purchase being above €250, so I paid €385. Depending on where you are, import VAT may apply.
It certainly blows the T-962A out of the water, and the €100 or so premium over the T-962A is well spent. The extra 100Watts may not be very significant, but the internal fan sure does make a world of difference. And more importantly: it is not a death trap out of the box, as is the T-962A.
The only major issue may be the volume of the control unit fan, which is a bit on the loud side. All in all, it's a solid unit for a good price for everybody that just wants something that works out of the box without having to tear it apart and do several mods to make if safe or performant.
As i use this unit, i will amend this post with information that occurs in long term use.

You can use an FTDI's USB to RS232 cable if you want. I don't honestly remember where did I get the software (I got my oven back in 2020), perhaps I contacted the seller and he provided it. Attached are a couple of screenshots (the oven was not connected when I took them). The only interesting feature (not available via controls on the oven itself as far as I can tell) is that it seems to allow PID tuning. But to be honest I never felt the need to do that, not to use the software once I tuned the profile. I only use room temperature stable lead free SAC paste - TS391SNL50, since pretty much all of my boards have at least one BGA and so I don't want to deal with any potential issues arising out of mixing different alloys (all BGAs I ever worked with ship with balls out of SAC).

Overall after over 3 years of use I don't really have much to complain, I've ran up to 5 LF reflow profiles back-to-back (letting oven to cool down PCB to 50°C as a part of profile), and hadn't had any issues (my T962 was seriously overheating after just two profile runs). The only things I can think of in terms of improvements are either cosmetic (I wish it would have larger window so that I can mount a camera and see what's happening inside), or perhaps revamping a GUI to make it more user-friendly, but the latter is something I got used to eventually. I also wanted to replace the annoying fan, but decided to leave it be since I only ever have the oven on when I'm reflowing, and it's off at other time, so I can live with a bit of noise for few minutes.

They actually did not supply the software, and I haven't found a download for it yet. But you can access the PID parameters by holding the SET button while switching it on.

I have not yet tried the software with my ITECH RF-A350, but a download for the software is available at https://www.itechsmt.com/pages/download

The ITECH RF-A series reflow ovens are the same units sold under a different brand name, and still shipped by Zhengbang.  I doubt there are any differences other than labeling.
I still need to clear some bench space for the oven, but your experiences match up with mine so far - although I have not reflowed any production PCBs yet.

Over the last year before buying the oven I have bought more than 40 CL feeders from ITECH on AliExpress.  As you mentioned they can be a bit slow to ship an order, but once shipped the packages have arrived quickly with no problems.


--- Quote from: BreakingOhmsLaw on October 01, 2023, 06:03:32 pm ---
 The drawer grip is separated by a couple of fibre board washers to prevent it heating up.

--- End quote ---

1) Not fibre board, but mika paper.
2) The password for the SW from iTech will be sent to you by e-mail upon request.


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