Maintenance Guide

This page is missing:

Software updates.

Hardware upgrades.

Troubleshooting known problems. In progress

Repairing common failures. In progress

Tested replacement parts

Stating maintenance frequency

Maintenance Guide¶

Required skills and resources¶

Maintaining your pipetting bot doesn't require superhuman skills, just a little time and dedication. Here's what you'll need:

Time to spare: Set aside some time to clean, lubricate, and inspect the machine. Think of it as a small investment that keeps your bot running smoothly.
Replacement parts: Keep a stock of commonly replaced parts like belts, rods, and nuts. This minimizes time-loss.
A commitment to care: Following the recommendations on this page is your key to success. No fancy skills needed, just a desire to see your pipetting bot thrive!

Post-assembly setup¶

Note: This section is missing a proper tutorial. This section takes a couple hours.

Software updates¶

Note: This section is missing a proper tutorial.

To-Do: commands for updating are similar to the ones for installation.

Add links to relevant contents: use Mainsail, connect through SSH and use git pull, etc.

Hardware upgrades¶

Note: This section is missing a proper tutorial.

Lubrication¶

Lubrication is an important step in maintaining Pipettin Bots, as it helps to:

Reduce friction
Prevent wear and tear
Dissipate heat
Protect against corrosion

In addition to these general benefits, lubrication can also have specific benefits for different parts of the Pipettin Bot. Lubrication, for instance, can help to improve the accuracy of pipettes and reduce noise levels.

Some parts, such as the sealed bearings in wheels, are lubricated at the factory. However, other parts, such as the lead screws, nuts, gears, and belts, need to be re-lubricated regularly by the user.

Tip

If you are changing between different types of lubricant, we recommend cleaning away the original lubricant with isopropyl alcohol first.
Clean the parts before lubricating them. This will help to remove any dirt or debris that could interfere with the lubricant.
Be careful not to over-lubricate, as this can attract dirt and dust.

Here are some specific lubricants that you can use:

White lithium grease is a good general-purpose lubricant for metal-on-metal contacts (e.g. leadscres and brass nuts). It is relatively inexpensive and easy to find.
Silicone grease is a good choice for lubricating metal-on-plastic contacts. It is resistant to moisture and dust.
Synthetic oil can be used to lubricate the gears and belts. It is important to use a synthetic oil that is specifically designed for use with precision machinery. Also recommended for tools maintenance.

Instructions to lubricate 3D-printers or similar CNC machines: https://www.youtube.com/watch?v=Yn6FFd1ry9g

Belt tension¶

Pipettin Bot achieves motion using a system of pulleys and belts as explained here. For optimal operation it is important that the belt tension is maintained at the correct level. Excessive belt tension will contribute to premature bearing wear. Insufficient belt tension can also lead to reduced pipetting accuracies.

All axes on the Pipettin Bot have way to adjust the position of the motors until the belts they drive are tight. The main X and Z belts can also be adjusted by pulling from the belts on a free end, and anchoring it while tight.

Since belts stretch over time, it it recommended that the user occasionally measures the belt tension and adjust as necessary. This can be done with any device that allows you to measure audible frequency in hertz or even manually.

Here are some tips for adjusting belt tension:

Be careful not to overtighten the belt, as this can cause it to break.
If the belt is too loose, it will slip and cause the machine to malfunction.
It is a good idea to check the belt tension regularly, especially if you use the Pipettin Bot frequently.

Manual method¶

Adjust the tension until if feels right, by plucking the belt and/or pushing it near a pulley.

It works if you happen to have good intuition for it.

Assisted method¶

Instructions to adjust belt tension using a guitar tuning app.

Follow the instructions here: https://www.youtube.com/watch?v=tg9Co_1MyZo

Motor current¶

It may be wise to check on the temperature of the motors to adjust their current limits.

If you find that they are skipping stepps on heavy load, and are not too hot, consider increasing the limits

The procedures are described in the electronics guide.

Subassembly maintenance¶

Many technical documentation entries have specific maintenance information:

Testing¶

Note: This section is missing a proper tutorial.

Test replacement parts¶

Note: This section is missing a proper tutorial.

Maintenance frequency¶

Note: This section is missing a proper tutorial.

Troubleshooting known problems¶

Overheating¶

Stepper motors generate heat as they operate, and if the heat is not properly dissipated, it can cause the motor to stall or overheat. This can be caused by:

Dirt in the motion system.
Excessive ambient temperature.

How to Fix: Keep you machine maintained and clean. Check the manufacturer's recommendations for the maximum RPM and operating time of your CNC machine. Place your machine in a ventilated workspace.

Power Supply Issues¶

Issues with the power supply can show up in a number of ways, and can be due to insufficient voltage and/or power ratings.

How to Fix: Ensure that the correct power and voltage supply is used, and that the supply is still capable of producing the required current at the nominal voltage.

Machine vibration issues¶

Excessive vibrations can cause fasteners to become loose, uncomfortable noises, and calibration issues.

How to Fix: Manually operate each axis of the machine, trying different speeds, lowering the speed until no vibrations are found. Alternatively, look for loose parts or fasteners, or considering attaching side panels to the open sides of the aluminium structure. Adding weight to the assembly, ensuring proper contact with the supporting surface, or rubber feet can also help.

Repairing common mechanical failures¶

All you actually need to know, as seen at R-bloggers.

Now seriously, most parts can be replaced by 3D-printing new ones.

A pipette's tip holder is the only plastic part that can break and will need a CNC'ed replacement, but gluing cracks or breaks may be viable (we haven't tried).

Pipettin Bot common failures¶

Note: This section is missing a proper tutorial.

To-Do: Do tests on Pipettin Bot to learn more about its common failures.

Tool Changer Problems¶

Occasionally, you may face challenges with the tool changer:

The remote actuator may jam.
The leadscrew on the headplate may bind on tools, dropping them on the baseplate.

How to Fix: re-calibrate the remote's limits and tool post coordinates.