Saturday, April 22, 2017

Machining Plastic Today



I am starting to get a feel for this CNC machine settings with plastic and aluminum.

Over the last couple days, I have machined gears, bushings, and other bits and pieces for my latest build.

I forget that I had my CAM software set on climb machining so today my first parts were ragged looking. I also mis judged the thickness of a piece of stock and cut into the bed. I now am using a spoil board and a bit of tagboard under the part. I find cutting thru the plastic and slightly into the tagboard, maybe 0.1mm, the plastic on the bottom side has a clean edge.

I had to disassemble the CNC yesterday to solve a backlash issue on it. The ball screw ends are not done quite right and there is slop between the bearings and the screw making the x axis flex and pull a little bit.

I 3D printed a spacer to hold the bearing tight against the screw.

I also tightened up everything and am pretty confident now to use the thread lock on everything. I also discovered that several bolts had a chamfer head and were pushing the machine out of alignment when tightened. That has been fixed.

It is a good little mill, great design but poor quality assembly from the factory. It has taken me awhile to get it dialed in. So far it is working and not needing to send out to a machine shop for parts is immensely satisfying.

Once I get the current big project out of the way, I will be assembling the other 2 cnc machines in the shop, setting up a foundry and possibly buying a small seig lathe.

I also will re-start jewelery box production next month. I had to take a break from that because of a lack of workers. I got one hired to start next month.

2 comments:

Phil said...

I got a 7X10 Harbor Freight lathe for Christmas.
Now I see why they call it a lathe KIT in the forums I joined.
The tailstock hold down bolt was bent so it pulled it 1/8th of an inch off of center when it was tightened. I made a new one out of stainless at work.
The compound gibs were messed up and there were several other little items that had to be sorted.
After all that though, it's a pretty decent little machine.

I was thinking about you the other day when I found a site from a Youtube where the guy was giving his thoughts on a qhick change tool post he got from them.
The name of the place sounds like a porno site but they sell over 150K different items.
It's called Bang Good.com. I was wondering if you had ever heard of them.
I swear this is where Harbor Freight gets a bunch of their stuff.
Ridiculously cheap. The quick change post at HF is $99 most of the time and has mixed reviews.
The one at Bang good was on sale for $37.99 last weekend and comes with 4 tool holders. Plus they had free shipping.
Normal price is $47.99 and they sell out a couple times a week.
With all the gizmos that you build, you should check that place out.
Look under electronics and go to the bottom of the menu to machinery parts.
They have stepper motors, guide rods, bearings and all kinds of crap, dirt cheap.

admin said...

I seen them, but I usually buy from AliExpress. I get almost all my China stuff thru Ali now.