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DIY Laser Engraver Design, Build, and Control

For the last few years, I have had an idea in the back of my head that I want to build a laser engraver. Over a co-op term, I decided I would finally make that happen. I decided to take a different approach to this project than I have for other projects, I would make a complete design first, and hopefully remove all problems during the assembly by doing so. I was also not going to skimp on any safety features, namely a full enclosure, proper emergency stop switch, and ventilation + filters. Making the design first also made me want to add drag chains, a hinged magnetic lid, handles for transport, a removable laser head, and many other amazing features that I would not have implemented otherwise.

One of the reasons I decided to take this project now was that I recently learned about GRBL being ported to the ESP32 and some development boards available for purchase on Tindie. A Wi-Fi enabled laser engraver sounded like a great idea to me, so I bought some of the control boards, and some TMC2208 stepper drivers for silent motion that is backwards compatible with all other stepper boards. I had some NEMA17 steppers lying around from a previous purchase, and the laser is a 2.5W diode I had purchased from Aliexpress a few years ago in hopes of one day getting to use it.

Before printing all the parts for this, I upgraded my slicer to the newest Cura edition so I could take advantage of the Horizontal Expansion feature, which allows adding offsets for the amount of expansion that your printer has. It took a few test prints to get the correct values, but it was definitely worth it. The fan enclosures, electronics boxes, motor holders, and bearing holders all slide on the to aluminum t-slots very snugly, and will not be moving around unexpectedly.

The frame of the build is made with black anodized 2020 aluminum extrusion that I purchased from RobotShop, and held together with aluminum L plates and M5 bolts. This construction is way overkill for a laser engraver that does not have any horizontal forces on the moving head, but I decided to go for it anyways as it looks great and provides a great base for transport,  etc. The exterior dimensions of the frame are 500mm x 340mm x 140mm.

A slightly modified version of the traditional CoreXY belt system was used, keeping the 2 belts on separate planes instead of having them cross over at the end. This allowed to keep the belt paths clean and the overall size smaller. The rest of the motion system includes 8mm smooth rods, LM8LUU bearings, and GT2 timing belts and pulleys with integrated bearings.

The ventilation system is 2 low profile Noctua 92mm fans with a carbon filter in front of them. These fans fit perfectly between the upper and lower aluminum extrusions, and provide a decent amount of airflow even through the carbon filters – I would not have gone with cheaper fans, as they definitely don’t move as much air as these Noctuas.

Internal lighting was another feature that I felt necessary to include, so I used some waterproof LED light strips that I have from previous projects. This fits perfectly inside the t-slot aluminum extrusions, and provides great lighting on the inside.

The enclosure is made from transparent orange acrylic. I knew I wanted the engraver to be enclosed, but I also wanted to be able to see what the laser is doing without opening the lid. The laser has a blue / near-UV wavelength, and I have heard that orange acrylic tends to absorb light of this wavelength. While I never actually verified this, I can say that looking at the laser dot through the acrylic is definitely different that without. I had originally decided to go with some laser shielding sheet from JTechPhotonics but once I realized that would mean spending a couple hundred dollars for the amount of acrylic I had needed for the design, I decided to just use some normal transparent acrylic. That lead to another search for a reasonably priced supplier that brought me to plasticworld.ca, where I was able to get the acrylic and the glue that I needed for around $100, and shipping was only $25 which was also a steal. While I was designing it, I also added some black acrylic accents to make the build a little more appealing, which turned out great.

As for gluing the acrylic together, I did not want to take shortcuts here either. There is one universally recommended glue for acrylics, also known as acrylic cement, solvent glues, or plastic welding, the Weld-On 4 and Weld-On 16 glues, which melt the acrylic thanks to some methylene chloride, and chemically bond the sheets together. This essentially creates a single sheet of acrylic once it is cured.

On the electrical side, I implemented a number of key safety features. An emergency stop switch, a large rocker switch as the main power button, individual toggle switches for the lights, fans, and laser power, and of course a fuse. These are all contained in one box mounted on the aluminum extrusions and the other box includes the ESP32 GRBL controller and the laser driver board.

The laser bed can be dropped out from the bottom using thumbscrews. I made this using a 1/4″ plywood wasteboard, a thin aluminum sheet to prevent burning through the plywood, all enclosed with aluminum angles to protect the sharp edges of the sheet metal.

I’m super happy about how this build turned out, and how close it looks to the original model. I think that’s a testament to how much planning can help a project run smoothly.

The next steps on this project is to clean up the wiring a little bit, then start the final testing. I have already verified that the motion is smooth (and pretty much silent thanks to those TMC2208 drivers) and that the laser works. Now I have to put the two together, find an optimal federate, and then find some software that will allow me to engrave images!

The first tests on this machine were engraving squares and circle with G-Code I wrote myself. After a long process of focusing the laser, I got some amazing and consistent results. I wanted to use a vector graphics platform to control the laser, and found a laser tool for Inkscape from JTechPhotonics. It took a little while to get it properly set up and useable (partly because the X-axis on my machine is reversed and the GRBL invert axes settings don’t seem to be playing nice with the CoreXY system), but once that was complete, I had a fully functional laser engraver. The first image I engraved was my logo, of course, on the same test sheet I had been using for the squares and circles!

Project By: Micah Black

Written By: Micah Black

A bunch of pictures of the design and build process can be found below.

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Laser Cut Nerf Ball Shooting Lego EV3 Tank

For the final project of my 1A term in Mechatronics Engineering, we created a laser cut tank with the Lego EV3 kit (this was required) that shot Nerf balls, all to achieve a very special purpose: to remove the geese from the University of Waterloo campus.

There are lots of pictures of the tank below, and our design reports are attached as well, but I would like to highlight something here as well. Before going further, I would also like to give credit to my amazing groupmates Caleb Dueck and Lukas Wormald. This project was truly a group effort, and I could not have asked for better groupmates.

The treads are made out of laser cut 3mm MDF board. Using cutting a flexible pattern in to the wood, we were able to create a fully functioning tread. We attached both ends of the tread using 18AWG wire loops soldered through holes in the ends of the treads. The gears were made from This may not have been the best option for the treads, but it worked fairly well and was easy to do. The treads were not durable in the wet weather outside and one of them broke as it got wet and soggy.

The ball hopper mechanism was inspired by the design of paintball hoppers, and laser cut out of 3mm MDF. It worked very well at slow speeds, and was very repeatable. The top cover is attached with magnets and is removable in order to reload the hopper.

If we were given more time and resources, we would like to have made the balls fire faster and further using compressed air instead of a spring. However, the spring powered solution worked fairly well after some tuning, but would not fire as straight or as far as was originally planned for.

Using the Lego EV3 Robot kit was a requirement for this project, driven by the school, as these kits are easy to debug. If we were given more time and more freedom, we would have used an Arduino based platform instead, as this gives more expandability, power, and features.

The design report that we produced covering all the design decisions that were made is available here.

Videos of the robot in action can be found here.

Project By: Micah Black, Caleb Dueck, Lukas Wormald
Written By: Micah Black

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Touch Sensor Piano PCB Kits

Again, a long overdue project article, but I am slowly getting through them.
This project originally started when I made a mini piano on a 400 point breadboard with screws as the touch sensitive keys. I was looking for an easier way to make keys that are secure, but extremely easy to make and assemble. The ideal solution would have been a tool-less, solder-less version that costs almost nothing, but I have yet to find such a solution. So, I designed a PCB to the 3 components of the piano, and used very large, circular SMD pads as the touch sensitive inputs.
Making a PCB allowed for a much smaller footprint, as well as easier assembly although there is soldering involved now – for me it is easy, but for others possibly not.
I may get to the point where I offer this kit as a beginner’s electronics kit, or as soldering practice like many kits I have seen on eBay.
After a year or so of using it and watching other people use it, I would have made the touch pads bigger, and would love to figure out a way to play more than one tone at once to create a harmonic.

Project By: Micah Black
Wirtten By: Micah Black

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Backlit Display Boxes for Decoration

This article is long overdue – it is for a project that I completed while still in the early years of high school.
The same goes for many of the next articles and projects I will be posting.

One day, I decided it would be cool to mount the boxes of computer parts on the walls and backlight them with LED strips. The next weekend, that is exactly what I did.
I used some 1cm x 1cm wooden strips to create a square slightly smaller than the sizes of the boxes that I will be mounting. To those squares, I attached the LED strips which were different colors to match the main color of the boxes. Once mounted, this created an effect somewhat like a floating box, with the light coming from behind, and no visible shelving to hold the box up.
To mount all this to the wall I chose the non-permanent method of double sided tape in the form of 3M command strips. I did not want to damage the boxes either, in case I ever needed to return any of the parts that they originally contained, so I used adhesive backed velcro to them to the wooden frames.
Now for the power, these LED strips need 12V which is perfect, as I have a computer power supply that provides 12V for the overhead lighting as well. I stuck an extra connector and switch on the end of a pair of wires and connected that to the closest box. To attach the rest of the boxes, I soldered wires between the 12V and GND traces of the LED strips, at the closest points between the boxes.
Fast forward a few years to when I am now writing the article, I am somewhat surprised that these held up so long. The 3M command strips are just now starting to lose their stickiness. As for the lighting, it still works perfectly, but I did not use it as much as I had expected. The LEDs were too bright to wire in to the main light switch, so I left them on a separate switch and only really ever used them as a showpiece.
If I were to do this again, I would make the LEDs dimmer by driving them from 9 or 10V instead of 12, and wire them in to the main light switch so that they are not too bright.

Project By: Micah Black
Written By: Micah Black

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iPhone 4S Phone Battery Failure (Chinese Replacement) and some Project Thoughts

I have always been a fan of fixing my own stuff. So when my iPhone battery died, I bought a cheap Chinese replacement and a screwdriver kit from eBay to replace it myself following an iFixit guide. The process was super easy, and I had everything working again in less than 10 minutes. However, this did not come without its consequences.

A few days ago (months now), while charging my iPhone 4S – yes, its old but it works – , I heard a ‘pop’ and felt the phone expand.
I took the case off as quickly as I could, and saw that the back of the phone had popped open because the li-ion battery had swelled up – never a good sign.
Surprisingly, the phone was still on at this point, so I shut it off and tried to get the back panel off. I took out the 2 screws, but before continuing to remove the battery, decided to turn it back on and get the pictures off of it.
I wasn’t sure if the battery was going to continue expanding when I plugged it in to my computer to take this pictures off, as this would also continue charging it. In the few minutes that it would take me to get the pictures off, it would not transfer too much energy to the battery, so I decided to take the chance.
I was able to successfully remove all the important data, then unplugged the phone and removed the battery without further problems.
Let me be clear that this battery was NOT the original iPhone battery. I had replaced it about a year and a half ago, with a cheap replacement battery from eBay. I wasn’t expecting the replacement battery to last a long time, but it managed over 500 charge cycles, which is not bad for a cheap chinese battery. It is definitely much better than those ‘UltraFire’ 18650 cells out there.

I have been buying Chinese parts for years, and have never had any problems with them, when treated correctly. Batteries are one thing that I will avoid buying from China in the future.

This also speaks to a project philosophy that I have been thinking about and working on recently – If its worth doing, then its worth doing well. Chinese batteries are one of those shortcuts to completing a project, but not doing it well. Sometimes, it is worth the money to just get the right components. All the Arduinos that I use are Chinese clones of the original open source Arduino boards. They are cheaper, but they function just the same. None of the 50+ that I have personally used have ever caused any problems or dangerous situations to arise, so until the day comes when one dramatically fails (more than magic smoke), I feel completely safe using them as long as I treat them well according to the manufacturer’s specifications.

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3D Printer from old DVD Drives

Again, another project that I completed (I tried at least) long ago and never wrote an article for.
After seeing some projects on instructables and hackaday that used DVD stepper motors to make 3D printers and laser engravers, I decided that I would try my hand at making one.
I had lots of old DVD drives on hand from electronics recycling centers, and the electronics I purchased for under $50 from aliexpress.
I used a RAMPS 1.4 board, an Arduino Mega, and the A4988 stepper drivers for this, as they are extremely cheap, and I didn’t want to spend a fortune on this.
For the extruder, I bought one of the E3D clones, a PTFE tube for the bowden adapter, and the cheapest NEMA style stepper motor I could find – which turned out to be a bad idea, and there were no designs for filament feeders that fit this motor, and I didn’t want to spend the time to design one.
The frame was built out of MDF cut by hand, and 3D printed right angle brackets and M3 bolts and nuts. I was surprised how well the 3D printed bolts and nuts stood up, and the frame was very rigid.
As for the Y axis, I attached one DVD drive slider to the bottom of the frame. On top of the DVD reader sled, I attached a raised flat surface held up with springs and bolts (to allow for levelling). This surface was a 50x50mm piece of steel from one of the DVD drive casings. As a print bed, I think this would have worked fine, but I never got a chance to test it actually printing.
The X axis motion was again a DVD drive mounted to the vertical part of the frame. The DVD drive sled slides horizontally like a Prusa i3 would. To this drive sled, I attached the cover of a 2.5″ hard drive to give me more surface area to attach the Z-axis to.
Up and down motion for the Z-axis was achieved with another DVD drive mounted to the X-axis.
Connecting the stepper motors to the drivers required some prodding with a multimeter to figure out which pairs of wires were connected inside the 4 wire stepper from the DVD drives. Once the two pairs were figured out, they were attached to the RAMPS board, and were ready to test.
To the Z-axis, I attached the E3D clone extruder with a fan mounted on it. This choice of extruder (or maybe this would have happened with any extruder) proved to be the wrong one, as the DVD drive on the Z-axis was not powerful enough to raise the extruder.
The next part to mount was the endstops, and as I was mounting them, I realized I should have thought about this earlier. Some disassembly and custom 3D printed pieces were required to mount them, as well as a fair bit of hot glue, which I was trying to avoid.
Then the software – I opened up the Marlin configuration file and started modifying the values that I knew had to change. This was mainly the travel limits for all axes.
Once everything was mounted and wired up, the testing started. I connected the Mega to my computer, and opened up Pronterface to control the printer. Through this, I was able to determine the correct steps/mm values to plug in the Marlin. The other thing that this testing showed was that the stepper motor for the Y axis worked really well. However, the same cannot be said for the X and Z axes. The X-axis moved very slowly, and did not have smooth motion. The Z-axis, without help, did not move at all while the stepper was getting very hot. To try and fix this, I tried to add a counterweight (an 18650 cell) for the Z-axis, but that did not help at all.

One of the big mistakes I made while designing this was thinking of it in terms of separate items, and not worrying about attaching them until I got to that step. This caused some problems where parts would not attach together properly, and after a few hours of rigging something up, I had found a way to make it work but it was never elegant, repeatable, or sturdy enough.

Project By: Micah Black
Written By: Micah Black

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Simple Arduino Pong Game

Another one of those long overdue articles. I originally created this pong game 3 or 4 years ago, but it has gone through several great iterations since them.
This portable pong game has been a work in progress for many years. The components have stayed the same, but the enclosures and format have changed a fair bit.
The first version was created on a breadboard and was mostly just a proof of concept and a platform to figure out the code.
The second version was built inside a 3D printed enclosure and was a mess of wires inside.
Next version (number 3), I created on a 7x9cm perfboard and managed to keep the wiring a little bit neater, but it looked much better than previous versions with the added benefit of being more compact.
For the final version (number 4), I designed my own PCB to hold all of the components, with an easily replaceable battery holder.
As mentioned earlier, the circuit stayed the same throughout all versions (with the exception of a power LED on some). So let’s take a look at what that circuit consists of. I used an Arduino nano to control everything, a 1.8″ LCD display, 2 10K potentiometers, a switch, a TP4056 charge and protection module, an 18650 cell, and a 5V boost converter. These were wired up in logical fashion so that the 18650 cell was protected and the voltage would be stepped up to 5V for the system, and the Arduino communicated with the LCD over SPI while using the potentiometers as analog inputs to control the paddles.
For programming this, and part of the original inspiration for this project, I found an example on the Arduino website that showed 1-player pong, where the paddle could move anywhere as the ball would bounce off of it and the edges. I modified the code for this to make a 2-player version.

By far, the custom PCB version is the best because it is compact, neat, durable, and easy to wire everything up. If designing the PCB again, I would definitely use a different software than EasyEDA, as the one thing that was especially annoying was the UI. I could not figure out how to create rounded corners on the PCB, and their guides were not much help either. Since designing this board, I have figured out how to do that, but I still don’t enjoy the interface.
As for improvements on the code, there are plenty of things I would change – the main ones being a better menu, text facing the right way, and the ball not removing parts of a dividing line. When programming this, I just programmed it up to the point that it worked, and then stopped making improvements, which I somewhat regret now, but is not something I am going to go back and fix, as I have too many other projects that I am working on now.

Project By: Micah Black
Written By: Micah Black

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My Vision for A2D Electronics

After spending 4 months away from Ottawa (and my business) at university, I wanted to figure out where I want A2D Electronics to be in the future.
I have spent a fair bit of time figuring out how to make this less work for me and potential future employees, but I also need some direction on where this business will be going in the future.

A2D Electronics exists to provide electronics at a reasonable and affordable price so that anyone and everyone can start making things. It does not exist to make me money. When this started almost 3 years ago now, I realized that the Ottawa maker community had a need for quick access to parts, and I could do something to help that. It was an idea that filled a need and one that I thought could make me some money.
Don’t get me wrong it does make money, but only enough to cover the projects that I make and post and some extra to reinvest in inventory and pay a little towards university. The most valuable things that this company has given me are first and foremost the connections that I have made, but also a feel for how business works on a small scale.

So where is this going in the future?
I want A2D Electronics to continue serving the community. From here on out, that is the main goal.
Before we take a look at how that will happen – let’s take a look at the current situation first.
The most time consuming tasks are restocking and re-ordering inventory, packing orders, scheduling local pickups, and adding new products. The biggest problem here is that I don’t have much time – between working full time on co-op, managing my own projects, other project, involvements in makerspaces and the Midnight Sun student design team leaves me with very little time. If only I could make myself an army of robot minions…
To continue serving the community, my focus will have to shift from being an order-packing robot to a community servant.
Making those tasks easier, more efficient, and streamlined has been on the back of my mind for the last month or so, and I have come up with several solutions that will be implemented in the near future. However, these changes alone are not enough to better serve the community.
One idea that I would like to flush out is to have ‘vending machines’ for electronic components in Makerspaces around the city. These would be amazing, but how would you keep track of everything and accept payments? Those are the questions that I have been dealing with.

So how does A2D Electronics better serve the community of makers?
By making access to components easier, faster, and more affordable. Doing this will mean flexible pickup times, possibly multiple locations, more products, and increased efficiency.
For the next few months, those items will be my focus.

Written By: Micah Black

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LiitoKalaa Engineer Lii500 Reliability, Accuracy, and Repeatability Test

Accurately testing 18650 li-ion cells is a very important step in the process of re-using cells from laptop battery packs, or designing a new battery pack in order to create matched modules and maintain a minimum amount of balancing current to keep the modules balanced.
During my first term at the University of Waterloo, I joined Midnight Sun, the solar car student design team and am working on designing a new battery pack for the next car, MSXIV (Midnight Sun 14). During this process, we are looking to accurately test every single cells that we putting in to the car in order to determine their capacity and internal resistance. This will allow us to create perfectly matched packs if the testing is completed accurately.
New cells are being used in this car, and the tests must be able to distinguish cells that fall within the manufacturer’s specified tolerance ranges for the cells. That means that the testing method that is chosen must be accurate to 10mAh for the capacity and ideally less than 1mOhm for the internal resistance.
And so started my journey of figuring out how to test all the cells in a timely manner while not spending tens of thousands of dollars on proper commercial testing equipment.
Starting with, one of the cheapest and most popular cell testers on the market, the LiitoKalaa Engineer Lii500.
I have 9 such testers, part of my cell testing station, and used 9 different cells to test each one, one slot at a time.
Each module was tested with one cell in the same slot multiple times to determine the repeatability of a measurement in the same slot, then the cell was moved to a different slot to see how the measurements compared.
The results can be seen on this spreadsheet, and were somewhat surprising. For tests of the same cell in the same slot, the values did not vary too much, within a range of 20mAh. However, when the cell was moved to test different slots, results were changed to a spread of almost 100mAh for some testers, with the average spread between the 4 slots around 50mAh.
Given these results, these testers are unsuitable for determining small differences in capacity between a batch of new cells, but for testing cells from laptop pulls they are perfectly acceptable. Keep in mind though, that the results will be within a range of around 50mAh from the value that they show.

Test Conducted By: Micah Black
Written By: Micah Black

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Series and Parallel Cell Configurations

I do not claim to know everything there is to know about battery packs, but from building my fair share of packs, I am hoping to pass on a bit of knowledge.

In order to build a battery pack, individual cells must be configured in series and parallel configurations to achieve greater capacity and voltage.
Each cell has a certain capacity, voltage, and max current that can be determined from the cell’s datasheet. If a datasheet cannot be found, a general safe rule for 18650 style cells is a 1C (1 times the cell’s capacity) discharge rate.
There are a few basic rules to remember.

 

Parallel Connections:

Achieved by directly connecting the positive ends together and the negative ends together (+ to +, – to -).
Capacity of the cells are added together to achieve a higher capacity battery.
Voltage of the cells remain the same.
Before connecting all the cells together, be sure that all cells are at the same voltage (within 0.05V). If there is a large voltage difference between the cells, when you connect them in parallel with a wire (0 ohm resistance) then when connected together, the cells will try to balance out the voltage. With a larger voltage difference, the current flowing between the cells to balance them out will be large – and charging li-ion cells quickly will create heat.
Cells connected in parallel act as a single, larger capacity cell.
Another common question with parallel cell connections is if connecting cells with different capacities will be problematic. This in fact is not a problem. When discharging the cells with different capacities in parallel, the cell with higher capacity will discharge at a higher current in order to keep the voltage between the cells the same. If both cells discharged at the same rate, the cell with lower capacity would drop voltage quicker. Since the cells are parallel the voltage on each cell must be the same, so discharging cells at the same rate does not work. Both cells must maintain the same voltage, so the cells must discharge at different rates relative to their capacities.

 

Series Connections:

Achieved by connecting the positive end of one cell to the negative end of the next (+ of Cell 1 to – of Cell 2).
Capacity of the cells remain the same.
Voltage of the cells is added together.
Before connecting cells in series, it is advised but not necessary to balance the cells. The main drawback to connecting cells in series is that the cells must always be monitored to keep avoid over-discharging or over-charging individual cells.
The cells that are chosen to connect in parallel must ideally have the same capacity, age, and internal resistance (capacity is the most important) so that when charging the pack, the cells do not become unbalanced. When charging the pack, if one cell has a lower capacity than the rest, that cell will reach full charge before the others, but the battery will not be at a full charge voltage yet, so it will keep charging. The cell with a lower capacity will now be overcharged and risk heating up and going into thermal runaway. A similar thing will happen when discharging – the cells with a lower capacity will be discharged to a lower voltage than the rest and could be over-discharged if not properly monitored.
Because of this, it is strongly advised to have a Battery Management System (BMS) that is able to monitor the voltage of the pack and prevent over-discharging or over-charging cells. Higher end BMS systems will also include cell balancing – they will keep all the cells at the same voltage level either by bleeding off the extra energy in the high capacity cells through discharge resistors as heat (passive balancing), or by transferring charge of the high capacity cells to the low capacity cells through transformers or other methods (active balancing). Active balancing is generally the better option, as it does not waste excess energy, but it is more expensive to implement.

 

Naming:

A battery with X cells in parallel and Y cells in series is referred to as XPYS.
So a battery with 3 cells in parallel and 2 cells in series is referred to as 3P2S.
This battery has 6 cells in it with 3 in paralled, and 2 of those parallel groups in series. It has 2x the voltage and 3x the capacity of a single cell.

2S3P

3P2S

The order of the P and S designations in the battery can mean different things. I have heard differing opinions on about whether this 2S3P battery is the same as a 3P2S battery. Both batteries will contain 6 cells, but the order of how they are connected will differ slightly. A 2S3P battery will have 3 series strings of 2 batteries connected in parallel, while a 3P2S battery will have 2 series sets of 3 cells in parallel. The main difference with the 2S3P battery would be that there is no parallel connection across the first set of 3 cells. Each series string of cells should have its own BMS, as all 6 cells could be at different potentials (voltage). It is advised to go with a large parallel group of cells, and put those large parallel groups in series if possible, unless there are problems implementing such a system. When connecting multiple LiPo batteries in parallel through their power connectors, each individual cell should be monitored, as this is a 2S3P style system. A modular battery pack might also make use of this design so that some cells can be removed, while still maintaining the correct voltage to operate whatever device it is powering. The naming and the advice here are not strict rules, but just some of what I have come across on my extensive battery building journeys.

If interested in more information on lithium batteries, here is a great article.
It leans more towards information on charging and storage safety for LiPo batteries, but has tons of great information.