iTECH RF-Axxx reflow oven algorithm is outdated - Page 1
Forum section: electronics / general

author: F1GWR
author_rank: Regular Contributor
timestamp: November 18, 2024, 10:55:28 am
content: Beware! These reflow ovens only incorporates an old-style RSS (Ramp-Soak-Spike) algorithm. More efficient and safer RTS (Ramp-To-Spike, google this term), although easier to program in firmware, is not implemented. When asking to the company, they simply ignore the request and stick to RSS.Did anyone develop a RTS firmware for these RF-A series?

author: SMTech
author_rank: Frequent Contributor
timestamp: November 18, 2024, 11:55:50 am
content: Quote from: F1GWR on November 18, 2024, 10:55:28 amIt may not be entirely accurate to call RSS outdated, RSS exists because older and smaller ovens did/do not have the thermal output to produce a RTS process window that worked as they would struggle to deliver a ▲T across a board leaving you with all sorts of process issues. Fixing the issues by altering the ramp rate or peak temp introduces other issues and potentially damages sensitive components that want to keep TAL (or sometimes lower) as short as possible. Ideally you want a firmware that lets you adjust everything to match your paste board and component requirements as best as possible.

author: F1GWR
author_rank: Regular Contributor
timestamp: November 18, 2024, 12:15:54 pm
content: Almostallstudies (google is your friend) show that RTS gives more reliable results than RSS, even, as you said, if there may exist some drawbacks. Nothing's perfect. But all in all RTS is better. In addition my solder paste recommended profile is givenonlyfor RTS.My initial question therefore is still relevant.

author: SMTech
author_rank: Frequent Contributor
timestamp: November 18, 2024, 02:23:05 pm
content: These studies all assume proper reflow ovens with 7 to 14 heating zones along a 4-8m heated tunnel. When we have that kind of equipment we are free to adjust each zone and the conveyor speed to deliver the reflow curve we are targeting and validate that using multiple probes on a test PCB to ensure the PCB and it components are being heated evenly.With a crappy hotbox from China you are far more constrained by what your oven is capable of, sure someone could attempt to write a RTS profile, but the oven itself may have some inertia that means it more easily achieves something resembling RSS. More likely, it achieves something way off target for either, at least judging by some experiences voiced on this forum for the product type.

author: 48X24X48X
author_rank: Frequent Contributor
timestamp: November 22, 2024, 01:30:35 pm
content: When I got their oven many months back, I did mentioned this to them. Coming from Puhui's oven before that, which implements RTS instead of RSS, I was skeptical at first. Puhui's curve were tightly controlled but the random cold spots is just too random. After tweaking the default lead free profile given on the iTech/Zhengbang's oven, it does perform way much better and consistent than Puhui's RTS. This boils down to the better quality build of the oven itself with less leaking on the corners and joints. This is from my limited experience of only using small IR based oven.

author: Kean
author_rank: Unknown
timestamp: November 23, 2024, 02:03:45 am
content: Quote from: 48X24X48X on November 22, 2024, 01:30:35 pmSame experience. I'll probably be buying a second RF-A350 (or 250).

author: JimboJack
author_rank: Regular Contributor
timestamp: November 27, 2024, 01:11:57 am
content: Hi can anyone give their reflow parameters for the RF-A350 oven via the serial interface , or just use the default profile 4 etc ?thksJ.