I've been 3D Printing for a while now.  After some minor exposure at my work with a Makerbot Replicator 2X I began to realize how a machine like this could help me achieve results without the expense of a home machine shop,   I do have a lot of equipment in my home shop, but 3D Printing certainly had potential to ease fabrication of my hobby projects.

I purchased a CTC Bizer since it was similar to the Makerbot, and my journey began.

Initially printing mostly PLA, the results were not stellar, but mostly ok.  I burned up a lot of filament on a ham radio project before deciding that PLA is not the best material for outdoor items, or when near the high voltage side of a ham radio antenna.  I made a brief dabble with ABS, but after 4 or 5 rolls of filament I moved to PETG.

Through the course I'd upgraded the Bizer firmware to Sailfish 7.X, replaced extruders, X and Y axis bearings, and switched to glass as a printing surface.

A brief rant about Chinese "Clone" products, and unfair business practice (9/7/2020):

Stupid Americans. We'll buy anything if it looks like a deal.

I'm not saying that all Chinese products are crap, but there are many unscrupulous vendors out there that prey on the unsuspecting consumer.  In this case the bearings used on the X and Y axes wore out very quickly.  They get noisy and rough due to poor engineering.  Ball bearings, unless specifically designed, are not intended for the fast jittery motion such as used in a 3D printer.  The axis needs to move far enough to allow the balls to roll through the cage and distribute the lubrication.  Bushings in this case are a far better choice, and plastic bushings are by far the best due to their low friction and tolerance to dust and other particulates. 

In addition to the poor engineering and cheaply made products, there is an unfair practice regulated by a department of the United Nations.  This department, the UPU has mandated that countries such as the USA must bear the burden of shipping charges from "Poor countries" such as China.  This is how you can purchase an item from China and receive it in your mailbox $2 with free shipping, when you can't ship locally for less than a few dollars. Reference: 

https://www.forbes.com/sites/wadeshepard/2017/11/05/how-the-usps-epacket-gives-postal-subsidies-to-chinese-e-commerce-merchants-to-ship-to-the-usa-cheap/#4167885640ca

You've all heard the phrase "Buy American", and many probably don't realize what our President Donald Trump is trying to accomplish as he battles the liberal - One World Government to Make America Great Again.  Recently he's installed a new head of the USPS and the liberals are up in arms.... Let's see how this unfolds.

About a year ago I purchased an FLSun Cube large format machine.  It is YACCP  (Yet Another Cheap Chinese Product) and was purchased with the expectation that I could fix any of the poor design, or cheap manufacturing issues.  The sum of the good parts is worth the price, but managing this is not something that should be tackled by the faint of heart.  Almost year later I'm amble to to get some good PETG prints off of it, however the quality is certainly not consistent.  I've modified many things about this machine, and replaced several right from the start.

The first to go were the X and Y axis linear bearings in favor of IGES Drylin bearings.  

Then the extruders were replaced with knock-off BMG dual drive geared extruders and since the machine didn't have capability of filament cooling fans, I downloaded, printed and installed the vampire carriage from Thingiverse for use with dual fans. 

The Z axis is driven by one output from Marlin feeding a single 4988 driver supplying two motors.  It was easy for the motors to get out of sync with no holding current, so I added a GT2 belt and pulleys to both acme screws.  This saved a tremendous amount of time and headache. In addition I added a 3DTouch (BLTouch knock-off sensor).

As long as Marlin needed to be edited, I decided to go to the latest version, 2.0 Bug-fix.

Next was a borosilicate glass plate on the hot bed (which may be soda-lime glass instead of borosilicate).

Then the Y axis roller bearings went out... Marked as ABEC 7, the bearing races were no harder than mild steel.  

Then the 12v- 20A power supply failed, (labeled as 300W, BTW 12V * 20A = 240W), replaced with a 12V - 30A Meanwell supply.  At the same time I replaced the MKS Gen L V1.0 board with a V2.0 because the FET for the heated bed was cooking the board traces.  At this time I added a separate MOSFET module that can handle the current of the heated bed, and reduced the max power to the bed heater from the Marlin stock 255 down to 200.

Sometimes we create our own problems.

The vampire carriage is a little flimsy and seems to allow some movement in all directions, but especially problematic in Z.  This has caused some aggravating issue with UBL.  Every print needs slight Babystep tweaking.  The adjustment is very touchy.  a little too close to the bed and the back pressure builds, then releases at inappropriate times in the print leaving a mess.  This typically happens on the first layer during the infill.

After extensive review of FLSun Cube carriages on Thingiverse, I decided to design my own carriage.  this is currently in process as of 9/7/2020.

More to come....