Printing Speed Optimization

Mercury 1.1 Printing Speed:

• Max print speed: 300 mm/s, Default Acceleration: 5000 mm/s2

• Max volumetric flow: 35 mm3/s

• Travel Speed: 500 mm/s, Travel Acceleration: 10000 mm/s2

Print Settings: 

Printer Settings: Retraction and Custom G-code

Filament Settings:

Speed Printing Optimization (PrusaSlicer):

2 key settings that drastically reduce print time: (I'm still experimenting with these settings)

Filament -> Cooling -> Slow down if layer print time is below 

• Slows down the layer to be at least however many seconds you set it. For example: Slow down if layer print time is below: 5 sec. If you have an infill layer that will take 1 second to complete at 300 mm/s, this parameter slows down the speed for the layer to complete in 5 seconds instead of 1. 

Print Settings -> Infill -> Reducing printing time -> Combine infill every

• Combines multiple layers of infill into one. For example: Combine infill every 2 layers. If your layer height is 0.2 mm, infill will print every other layer, but the infill line width will be 0.4 mm. 

Acceleration and Speed go hand in hand. You can set the printer to go a high speed, but this will mean nothing if your acceleration value isn't high enough and the printer never reaches this speed. 

At first I was tuning for very high acceleration and speed. This isn't necessarily a bad thing, however you sacrifice print quality and surface quality for higher speeds. I was still able to get some decent looking Voron design cubes and calibration cubes, but their surface appearances were still a little too messy for my liking. I then started tuning for quality after having done some testing to find my printer's speed and acceleration limits. 

I started to run into a problem where I could get successful prints at high speeds, but my cubes still looked terrible. It might seem obvious, but I came to the realization that I was printing too hot after reading some forums. Since I was printing at such a high temperature, the filament did not have enough viscosity, which led to inconsistent layer lines. After scaling back a Voron Design cube from 280 C (with PETG) to 255, the top layers looked better than the bottom layers.

Here's what I learned from tirelessly tuning and optimizing my printer: 

Key factors for high speed printing: volumetric flow rate, speed and acceleration, hotend temperature

High flow rate -> high speeds -> high hotend temp -> worse appearance

slower flow rate -> slower speeds -> lower hotend temp -> better appearance

The balance is finding something in the middle that's reasonably fast, but still looks great. 

Extrusion Multiplier: