Panda DTF With L1800 Printhead: Why the White Ink Mixer Runs Too Often After an Upgraded Pump/Mixer Motor (And How to Fix Over-Mixing)

Question:
I recently bought the upgraded pump and mixer motor for my printer from your site. Since installing it, the mixer seems to run much more often than before, and I'm worried it will wear out faster than it should. Is this increased mixing expected, or is there a fix? Right now it stays off for about 5 seconds, then runs for about 30 seconds. I'm using a Panda DTF setup with an L1800 printhead.

Answer

What you're describing is "over-mixing"

A cycle of off ~5 seconds / on ~30 seconds is much more frequent than what most white-ink systems need for routine agitation. White ink does require agitation to prevent pigment settling, but too much mixing is a real thing-and it can cause problems rather than prevent them.

Why it can happen after an "upgraded" pump/mixer motor

When you upgrade the pump and/or mixer motor, a few things can change:

1. The new motor may be stronger or spin differently
   A higher-torque motor can make the system "feel" like it's working more aggressively, even if the control signal is the same.

2. The controller/timer settings may not match the new hardware
   Many Panda-style DTF systems use a timer/controller to trigger mixing intervals. If the timer is set too aggressively (or defaults to an aggressive profile), it will run the mixer far too often.

3. The system might be responding to power/connection changes
   If the mixer is connected to a different control output than before, or if a controller is "resetting" and repeating a cycle, you can end up with abnormal on/off behavior.

What over-mixing can cause

Over-mixing isn't just about motor wear (though that's a fair concern). It can also contribute to:

• Extra heat and stress on the motor and bearings

• Foaming / microbubbles in the ink path, which can show up as inconsistent nozzle performance

• More vibration, which can loosen fittings over time

• In some setups, accelerated wear on the mixing mechanism (paddle, coupling, magnet stirrer, etc.)

Recommended mixing schedule (your proposed fix is on point)

Your instinct-and your proposed answer-is correct: this is over-mixing, and the fix is to adjust the mixing interval.

A good baseline guideline for many white ink circulation systems is:

• Mix ~30 seconds every ~2 minutes (30s ON / 120s OFF)

That schedule keeps pigment from settling without constantly hammering the motor. Different machines and ink viscosities may want different settings, but your recommendation is a solid "safe starting point."

How to correct it (practical checks)

Because these systems vary by controller style, here are the typical paths to fix it:

1. Adjust the timer/controller settings

   • Look for the mixer controller or timer module (often has ON/OFF interval dials or digital settings).

   • Set it closer to 30 seconds ON / 2 minutes OFF.

   • If it's a digital timer, confirm you're editing the correct parameter (some have separate "work" and "rest" settings).

2. Confirm the mixer is plugged into the correct port/output

   • If it's plugged into a "continuous" or "rapid cycle" output, it may behave like what you're seeing.

   • Make sure it's on the intended "mixer timed" circuit.

3. Watch for "reset looping"

   • If the controller is power-cycling or resetting, it can repeat a short loop.

   • Check the power supply stability and connections. A loose barrel connector or weak supply can cause odd cycling.

4. Listen/feel for abnormal load

   • If the mixer is binding or encountering resistance, some controllers will behave strangely (or the motor may run hotter).

   • Make sure the agitator spins freely and isn't rubbing a tank wall or pulling against thick sediment.

Is it "expected"?

It's not expected for the mixer to run at 5 seconds off / 30 seconds on as a normal long-term behavior. It's more consistent with an overly aggressive timer setting, a controller default, or an incorrect connection/output. Once you dial the timer back to a reasonable interval (like 30 seconds per 2 minutes), you should be in a much healthier range for both ink stability and component lifespan.

Addressing printer issues can be complicated because the problems are hands-on and depend heavily on the machine's exact configuration and what it's doing physically. Because of that, we're not able to provide remote troubleshooting, repair instructions, or direct support for printer repairs. We do offer an in-person evaluation and repair service through our local diagnostic facility: printer repair service (https://bchtechnologies.com/printer-repair-service). Due to high demand, service is first-come, first-served, and it may take a few weeks before you're able to drop off your printer. Our services are structured to repair either an entire printer or specific parts, with clear instructions on how to proceed. We also acknowledge that our rates aren't the most economical, so we strongly encourage self-help through online research first. You can begin by checking YouTube-especially our channel homepage: BCH Technologies on YouTube (https://youtube.com/@bchtechnologies). To find relevant videos quickly, use the search icon near the "About" section on the right side of the menu bar. I receive dozens of messages every day asking if we have a video for a specific issue, and after nine years of creating videos, it's tough to remember every single one-YouTube's search tool is the fastest option, and it may also recommend helpful videos from other channels.

Thank you again for your support and for choosing BCH Technologies for your parts. We truly appreciate it, and I hope adjusting the mixer timing helps protect your system and keeps your white ink performing consistently.