Applications and Implications

The assignment for this week is to propose a final project masterpiece that integrates the range of units covered.
It should incorporate
  • 2D and 3D design
  • additive and subtractive fabrication processes
  • electronics design and production
  • embedded microcontroller interfacing and programming
  • system integration and packaging

    • Final project presentation

      My final project is to make a vinyl record cutting lathe.

      What will it do?

      The machine will be able to engrave music on a blank vinyl record or other compatible plastic blanks like CD, DVD, PVC, etc.
      I will mainly concentrate on the engraving head and the X gantry mechanism, and will use a high torque turntable for the spinning part at first.

      Who's done what beforehand?

      It seems that not much has been done since the 70s and that most people are using old cutting lathe from that time or even older.
      But there has been a few DIY attempts by enthousiasts with more or less success.
      We also start to see emerging a few commercial projects.
      Links can be found on my project page.

      What will I design?

      The most critical part I need to design is the cutting/engraving head.
      This seems to be the most difficult according to most of the people that have tried making their own.
      I also need to design a strong and efficient motorized X gantry that can be easily adjusted mainly for the Z leveling.
      The arm that will hold the engraving head will also need to be designed.
      And also a dedicated PCB.

      What materials and components will be used?

      For the frame I will use 40x40mm extruded aluminium.
      For the X axis I will use one that I already have and will adapt it and get it motorized.
      So a stepper motor like a Nema14 or Nema17 will be needed.
      I also have a small mechanical axis that I can use for fine tuning Z leveling.
      The engraving head will use 2 small full-range speakers. These need to be small enough but efficient at reproducing a wide and balanced frequency response.
      For my project I will use 2 BF-32 (8 Ohm) based on advices found on
      I will also need an embossing needle. I might have to test quiet a few before making my choice based on the results.
      For all the other parts like the arm and head mechanism, all the parts will be 3D printed.
      The electronic part will reuse the Satshakit board that was made in earlier weeks.
      And I will also need a few nuts, bolts and washers.

      Where will they come from?

      Most of the parts I will use have been salvaged from the trash but should be easy to buy if needed.
      I bought my BF-32 speakers from RS-components but they can be found from other vendors.
      The needle I will start with is a cutting one used on the Roland GS-24 vinyl cutter we have at the lab.
      Nema stepper motors are easily available from a lot of vendors and one should try to find the best deal locally when possible.

      How much will they cost?

      If you can salvage parts from the trash it's likely to cost you nothing...
      But of course you don't find 40x40mm aluminium extrusion in the trash everyday (I've been lucky).
      Depending from where you buy them, a 2m long 40x40mm aluminium extrusion will cost about 45€. My design uses 3m.
      The speakers I bought from RS-Components cost me 15€ each. So 30€ for both.
      A set of 15 Roland GS-24 needles can be found for about 5€.
      A Nema14 or Nema17 stepper motor costs about 40€ but can be found for less.
      I opted for a Nema14.

      What parts and systems will be made?

      The parts that need to be made are all the 3D printed parts.
      It includes the parts that will connect things together, the arm and the engraving head.

      What processes will be used?

      Mostly 3D printing.
      But depending on the sturdyness of some critical parts, I might need to have them made in metal.
      If this is the case, I might have to make a silicon mold and cast them using Cerrotru.

      What questions need to be answered?

      Still quiet a few at this stage...
      What kind of needle will give me the best results?
      At which angle should the needle be to the engraved material for best playback fidelity?
      Will it engrave in mono or stereo?
      Will the noise coming from the mechanism and motor have an impact on the recording, and how to minimize or eliminate it?
      How deep should be the engraved groove, and how much pressure need to be put on the needle?
      How do I need to prepare the sound that will be engraved?
      What should I be aware of when preparing the files to be engraved (frequencies, volume, filters, equalization, etc.).
      And at least but not last : will it work and if it doesn't, why?

      How will it be evaluated?

      It's pretty hard to say...
      Will it work, kind of work, or not at all?
      I'm confident and I'd like to say that I should at least be able to hear something during playback.
      But how will it sound? There are so many factors that might influence the playback quality!
      But as a starting point I will be happy if I can just get some recognizable playback.
      It will be a good starting point that can only get better afterward by experimenting.
      I've seen several DIY projects that never came to the end, and just a few with pretty decent results.
      I have no other choice than experimenting and learning by myself and from my failures.
      So I know it's gonna be a long way to success...

      Resuming table

      Global cost resume
      What?Where?How much?How many?Total
      40x40mm aluminiumlocal supplier22€/m3m66€
      BF-32 speakersRS-components15€230€
      Roland GS-24 needles (set of 15)Aliexpress5€15€
      PLA spoollocal supplier28€1kg28€