Messages

51

Show"N"Tell ( Your Machines) / Re: Raskin Turret Punch

« on: March 25, 2014, 09:51:12 AM »

Here is a video of the punch in operation. Auto-indexing was tested here.

http://youtu.be/ZxPTUF_e0os

52

Show"N"Tell ( Your Machines) / Re: Prima Lathe conversion

« on: March 24, 2014, 05:44:40 AM »

I guess the most cost effective solution would be to go with the 40mm screw. Mine is 32mm. Extra inertia will result in slower accel and decel rates. Rack and pinion would be ok if you use a linear scale on the z-axis and use servo drives that can handle two encoder inputs (like Delta A2 series servos). You'll have to mount the servo with a gear box to the slide carriage for rack and pinion mechanism.

Zafar

53

Show"N"Tell ( Your Machines) / Raskin Turret Punch

« on: March 22, 2014, 07:38:21 AM »

Here is the latest retrofit. It's a Raskin RT-210-12 turret punch. 20 ton punch with 20 tool turret. 2 auto-index tool stations. Hydraulic servo ram with position control. 5 axes controlled by AC servo motors. 53 I/O's and hydraulic servo managed with UC300 motion controller and Arduino. Here are a few photos before, during and after the conversion. Will shoot a few videos next week.

Zafar

54

Show"N"Tell ( Your Machines) / Re: Prima Lathe conversion

« on: March 10, 2014, 03:59:53 AM »

My z axis ball screw is almost 900mm. I am using deep groove ball bearing at the free end. The x axis screw has no end support. It is just 250mm long. You can also try the rotating nut mechanism similar to the one used in early Bridgport series I CNC mills.

55

Show"N"Tell ( Your Machines) / Re: Prima Lathe conversion

« on: February 22, 2014, 08:58:42 PM »

The 10mm pitch ballscrews have good accuracy from your testings ?
Or would be better with 5mm ballscrews and 1:2 reduction ?

With this setup you have 15m/min rapids  is this speed in usable range or it is so much for conventional prismatic ways ?

You are right. The max rapid is too much for the conventional ways. I have fixed it to a slower 5000 mmpm. A 5 mm pitch screw would be better for this machine.

56

Show"N"Tell ( Your Machines) / Re: Prima Lathe conversion

« on: February 21, 2014, 11:16:36 PM »

What type pulleys/timming belts have you used ?
Have you any backlash with these pulleys/timing belts ?
Finally reduction is 1:2 and ballscrews 10mm pitch on both axis ?

I am using 3/8" pitch L sized belts and pulleys. No backlash. 1:2 reduction on both axes. 10 mm pitch on ball screws.

Zafar

57

Show"N"Tell ( Your Machines) / Re: Plastic Injection Molding

« on: January 28, 2014, 10:37:38 AM »

A good starting point would be to set the temperature of heater to processing temp for your plastic. A good source for finding the processing temp is the Modern Plastics Encyclopaedia.

58

Show"N"Tell ( Your Machines) / Re: Plastic Injection Molding

« on: January 28, 2014, 08:52:41 AM »

Maybe you should try milk bottles instead of soda bottles. Soda bottles are normally made from PET while milk bottles are mostly HDPE. HDPE's flow is better suited for hand molding. Put heaters on the lower half of the molten metal barrel. So that only the lower half gets melted and the top half is in solid state which you can push with a plunger. The reason your molten plastic gets solid in the runner might be because of less material flow for the mold size. Try a smaller cavity and runner size.

Zafar

P.S.  a few photos of your mold would be interesting

59

Show"N"Tell ( Your Machines) / Re: Plastic Injection Molding

« on: January 28, 2014, 06:05:37 AM »

Interesting project. I used to have a bunch of hand operated molding machines in my workshop 20 years ago. A couple of them are still stashed away in the attic. Those machines were used to produce low volume production parts and gave out good, precise results from ABS, PP and Acetal. We used virgin and dyed plastic pallets and mostly CNC machined mild steel molds.

Zafar

60

Show"N"Tell ( Your Machines) / Re: Prima Lathe conversion

« on: December 31, 2013, 09:47:12 AM »

vre,

The transformer is for getting 220V from 380V mains. The drives and the PC can run from 220V single phase, but I didn't want to introduce a neutral phase into the system to avoid line fluctuations. That's why the three phase transformer is there. Nut on my Z axis screw is single and on the x axis is double. No big reason behind that besides they were the only ones available at the time of assembly. For breakout boards I'll ask my friend Nooruddin, who did the electronics mumbo jumbo, for any tips.

Zafar