Engraving Tips & Tricks #2: Cooling, Feeds, & Speeds

The engraving process produces ultra fine particles that are too small to see which need to be collected for human safety.

Our original design calls for a mounted shop vacuum and a magnetically mounted Lexan shield.

This setup is simple & works great! Though its probably best used in a garage because a shop vac can be noisy. For use in an office or apartment I wanted another option…

So with the addition of one tiny 3d printed part, a fountain pump, & a 12″x7.5″x2″ aluminum pan I built a water cooling system!

I also added an optional printed shield/cover shown on the left side of the machine as a splash guard just in case!

Its an improvement all around! Its totally silent & the water cools the bit as it contains any airborne particles.

(The appearance of an aluminum foil tray is not our #1 choice to be sure. I’ve got a design for a slick black vacuum formed tray, but I wont pull the trigger until a later time.)

In addition to new hardware we improved our technique as well.

We learned through iteration to make software V2 smart enough to always keep the motors energized so you never lose your rotational position, even when a job is complete.

Keeping track of your position matters because if you lose power during a job you want to be able to pick up where you left off. But since a cup is round, there is no hard stop to home against. So I think its good practice to make a registration mark at the tool home position. A tiny dot as shown in the next picture, so you can line up your tool exactly where it was, even after powering down & removing/reinserting the cup!

We found this necessary after breaking a few bits during or experimentation process, trying to figure out the best feeds & speeds for different materials. Fortunately, this process will be easy for you since you can copy what we know works well!

Feeds & Speeds:

  • Tool Speed: The rotary speed of the Dremel tool; Controlled by the Dremel.
  • Feed Rate: The rate of motion of the machine; Controlled in Run Mode.

The default feed rate is a good value for drawing with a pen, 50mm/sec. That is, the pen will draw a 50mm line (2inches) in one second. Though, short line segments will take slightly longer because the machine also controls acceleration rates.

Acceleration control is necessary because the moving parts (tool & cup) have mass and are moving quite fast. If you try to move full speed then change direction suddenly the motor might stall & lose control of its position. The default acceleration values are adequate for 99% of cases. Though on the large glass stein in the first picture I found that I needed to reduce the acceleration rate by half.

Below are proven save speeds & feeds for engraving different materials.

  • Glass & Ceramic: Dremel Speed = 1 Feed = 7mm/sec
  • Painted Aluminum/Steel: Dremel Speed = 2.1 Feed = 15mm/sec
  • Pure Stainless Steel: Not recommended with this tool.

Real Stainless steel is a very hard material, well known for its resistance to rust and poor machinability. The Dremel Stylo will scratch it though the result can be more faint than would be desired, since there is no contrast as with removing a painted coating. So for this material we recommend a different tool, but that is a topic for next time!

Feed rate control in software
Dremel Speed Control

Published by EngineerDog.com

Michael is a modern mad scientist. Engineer by day, aspiring entrepreneur by night, and exhausted but loving parent at all hours of the day. He is always experimenting with inventions, small business ventures, and unnecessary home improvement projects. You can follow his adventures on his blog at www.EngineerDog.com

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