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Skyfire CNC Part 2 - Machining & Fitting

Posted by  7xCNC  Sep 1, 2013

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Skyfire, located in China, have developed a great small CNC mill and is now beginning manufacture - no struggling with a conversion of a manual mill. They call the it SVM-0

Part One covered making the blanks for the casting moulds.

Part Three will cover painting, assembly and alignment

Part Four will cover the electronics.

Skyfire are presently working on their website - we'll be sure to post a link when they have it up and running.

They are also working on a range of larger machines, with extended capabilities such as automated tool changer (ATC), and looking at producing lathes.

This article covers machining of the cast iron and initial parts fitting

The Table:

The table begins with a block of cast iron, machined to size. Multiple cutters are used in a horizontal mill setup to make this a quick operation. (Note the table being machined in these photos is not for the SVM-0, it's a bit bigger. Same principles and end result however).

Table slot cutting on horizontal mill

Table slot cutting on horizontal mill

Table slot cutting on horizontal mill

After the basic slots have been made, a T slot cutter is used to make the slots into 'T slots' to allow clamping:

Table T slot cutting

Slots roughed out, the SVM-0 table looks like this:

Table, slots cut

Then the bottom must be machined - precise mounting points for bearing blocks, and slots and mounting holes for linear rails:

Machining table ballscrew bearing block seat

Drilling linear rail mounting holes in back of table

 Mock-up of rails on table

The Saddle:

The saddle is the bit sandwiched between the base of the machine and the table. It's where the linear bearing blocks mount for the X and Y axes. It starts life as a rough cast block

Saddle, rough cast

The ball nut mounting area and the flats for linear bearing mounting are milled, and then holes drilled. This must be done on both sides for X and Y axes:

Saddle, initial machining

Saddle, holes drilled

Saddle machined:

Saddle, machined

The Column and Base:

Machining proceeds much the same as for the table and saddle

Column Machined

Rails are fitted:

Column rails fitted

Then the ballscrew:

Column linear motion

Base with rails

 It's vital to get the stepper motor mounts precisely aligned with ball screws to ensure smooth motion and no binding. A alignment jig is made for this purpose. The silver rounded part below presses into the black drilling jig. The flat on the silver part avoids interfering with the base casting.The silver piece then presses on to the ballscrew, and the black jig is used to drill the mounting holes for the stepper mounting plate.

Stepper mounting drilling jig

Stepper mounting drilling jig in place

The Head:

Head roughed

The spindle motor sits nicely out of the way inside the head, attached to a mounting plate, with slots that allow the belt to be tensioned.

Spindle motor and mount

Spindle Motor Mounted

Alignment:

Careful alignment is vital. This begins with precision granite squares and use of the dial test indicators First one rail is aligned to the table edge:

Linear rail aligned to table edge

Then the second rail is aligned to the first

Second linear rail aligned to first

Table rails installed

The same process is repeated for the Y axis (the base) and the Z axis (the column)

The saddle is installed on the table:

Saddle installed on table

And then both are installed on the base:

Table on base

 

The basic components of the mill are now together:

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