2013-10-24

Soundproofing the TravelCNC


The TravelCNC already has an inner lining of Basotect acoustic foam on the inside.
(Not all of it mounted yet because I'll improve some of the cabling hidden below the foam.)
This helps a great deal with high frequencies.
For the low frequencies I have a heavy, 10mm thick rubber sheet below the actual machine.

It turns out that this is not enough. I get a great deal of vibration that can actually be felt on the wooden stage box.
Next idea: there are 4 bolts going through the rubber and mounting the machine to the case.
I'mm try to widen the holes in the wood and install sound insulating bolt anchor fittings to insulate the bolt from the hole in the wood.

...let's see of that helps.





2013-11-13 UPDATE
I finally finishd the sound proofing




2013-10-22

Fixing the 4th axis on the TravelCNC and breaking my tools


Since I mounted a larger stepper motor to the 4th axis on my TravelCNC (portable hobby sized CNC in a custom flight case), I needed to raise the 4th axis by 10mm.
Else the longer stepper would collide with the frame.




This means that the tailstock is now too low.

So yesterday and today I milled myself a spacer out of some wood to keep the tailstock at the correct height.



It worked...but when I tried to use it, I made a terrible mistake.
I wanted to use the edge finder to find the right and left edge of the cylinder I mounted.
I knew it was perfectly round, so the center of rotion would match the center of the cylinder.
....so I mounted my mechanical edge finder...switch on the spindle to rotate it slowly

...and forgot that the spindle was still set to 10'000RPM.
It ripped my trusted edge finder apart.

Now you can get mechanical edge finders for 3-4eur in China, no problem.
You can even get cool electronic ones for 10eur.
However all the mechanical ones are 10mm shank and the electronic ones 20mm shank.
The maximum my ER11 collets can mount is 7mm.

I would really like to modify one of these electronic ones. Attach it to the electronic probe input and find edges extremely accurately without jogging back and forth.
However the back is also the battery cover. So I can't simply mill it down from d=20mm to d=7mm. :/

2013-10-19

MY BMPCC review

I just received my Blackmagic Pocket Cinema Camera last night.
In this blog posting I'm trying to collect my findings about it to help others decide on it's maturity.

untested


  • LANC focus control
  • LANC IRIS control (command codes unknown)

confirmed features

  • LANC start+stop
  • very fine and organic grain

confirmed, known issues

  • very low audio levels with internal or external microphone (Sennheiser MKE400 with levels "+")
  • constant white noise in audio
  • Focus button is extremely slow (2-4 second for a Leica lens that focuses in less then 1/10s)
  • no OIS on 14-42PZ
  • extremely short battery life
  • seldom dropped frames (3-4 frames on a total of 45min of 1-5 minute recordings) using Patrion Memory EP-Series 64GB UHS-1 SD-card

new issues

  • 14-42PZ does not shut down properly on BMPCC (lens doesn't collapse)
  • LANC cannot control the zoom on the 14-42PZ, ,14-42 II, 42-175 PZ and 100-300 using the Manftotto 484LNC (my fault. DAQ states that ZOOM via LANC is unsupported. :( )

feature requests

  • manual aperture control in the menu
    • you can do that. You have to press IRIS and the up+down buttons right below. Imposible with one hand. Difficult with 2 hands.
  • display of remaining minutes on SD-card
  • audio levels
  • deletion of clips in camera
  • formating SD-cards in camera

Links 

2013-10-17

Tailstock height adapter for my TravelCNC

The original 4th axis on my TravelCNC was mounted so low, you can't even extend the arms of the chucks beyond the diameter of the chuck itself without hitting the table.
It was also so weak, that you could rotate it with 2 fingers while it tried to rotate the other way with all it's force.

So now I have a NEMA23 longneck stepper with tons of holding torque...and I can't mount it because it collides with the table.
Luckily it already came with a 10mm high alumimum plate to be mounted on the T-Slots.
What I did was to mill a small spacer out of wood to get the tailstock to the same Z+10mm height because obviously both have to match.

As it turned out, I had the wrong tool diameter in my CAM and it was 2mm too short.
..but that's easily fixed with hand tools while cutting it out.
(I don't want to cut it out with the CNC because I have no scrap-wood below it to ensure a flat surface.)