Here is a summary of my progressive findings on the XK7113D CNC mill from WMT This page is work in progress as I set up the machine and begin milling with it.
Note: For the record I am not sponsored by WMT in any way. These findings are provided based on my experiences with the XK7113D CNC mill.
Although there may appear to be a large number of issues with the machine as supplied, none have proven to be show stoppers, and it should be understood that this is a relatively complex piece of precision equipment. Many of the issues identified have a link to the relevant page where they are discussed in more detail.
While it is premature to make a definitive conclusion at this time, on the basis of limited testing to date, the machine actually mills to specified tolerances. I rate the machine as moderate value for money. Potential purchasers are warned that:
- the control cabinet wiring will need to be checked by an appropriately qualified electrician, terminations tightened, and modified for protective earth safety.
- peripherals such as a fourth rotary axis are poor quality and degrade the machine performance specifications.
- Don’t expect to unbox the machine and be milling in a few days. Allow at least a few dedicated weeks to set the machine up, even if if you are familiar with Mach3.
- The order was handled expediently, but the machine took longer to manufacture than stated on the order.
- The machine ship factory to door in good time and in reasonable condition, complete with basic tools and accessories. But there is no spanner of the collet chuck.
- Mach3 demo software, a profile and a USB plugin were provided over the internet by WMT. You will need the USB plugin. The solftware is best downloaded directly from ArtSoft. You will also need to purchase a license for Mach3 from ArtSoft.
- I had some problems getting the machine to run under Mach3 due to an inadequate profile. This needs to be set up using the configuration menu in Mach3. Expect to spend several days setting up the parameters and calibrating Mach3 for the CNC mill.
- WMT have (in general) been responsive to inquiries and my one request for support. However, as you might reasonably expect, there may be communication issues between English and Chinese first language speakers, and WMT responses did not always result in resolution of issues (or clarification of the problem/question).
- Inspection identified swarf from manufacture in the Tee slots, on the linear bearing facings and beneath the Y axis bellow covers. This is considered poor manufacturing practice.
- There was bloom rusting on the bed, at the base of the column, on the Z axis brake, beneath the rotary axis, and on many of the machine screw heads. This is considered due to inadequate surface preparation (protective grease) prior to shipping.
- Earth was switched through the main rotary power switch. This is poor wiring practice. It was rewired to provide a permanent dedicated earth connection to the chassis.
- Phase and neutral were inverted to the control switches causing an error with the on switch lighting. This should have been identified at the factory through testing. It was rewired.
- The main DC rectifier heat sink was not adequately secured to the control cabinet and the associated filter capacitor was not adequately mounted and is too small for this duty. The heat sink was securely mounted and the capacitor was replaced and securely mounted.
- The machine is not fitted with an EMI filter. The Variable Frequency Drive (VFD) and stepper motor switching can generate a lot of mains noise and may be susceptible to noise from other equipment. I have fitted an appropriately rated EMI filter on the AC supply.
- There was a wiring fault with the spindle cooling pump. I suspect that the pump was never tested at the factory.
- The spindle motor cooling tubes were crushed and twisted within the spindle cowling and required replacement. This is due to poor assembly and inadequate testing at the factory. In replacing these I have relocated them to the left hand side of the cowing.
- The spindle motor power plug was poorly secured to the cable - a wiring issue. The connection had to be remade.
- The Variable Frequency Drive (VFD) for the spindle motor parameters were not set correctly for RPM display. These have been adjusted.
- The users manual is minimalist and not particularly helpful. Notable omissions include basic controls, maintenance and lubrication, a wiring diagram, and data sheets for the control cabinet modules (controller, stepper motor drivers, Variable Frequency Drive, ...).
- The fourth rotary axis has about one degree of axial backlash in the gear box. It is also mounted on spacer washers which do not ensure that the axis is parallel with the base. These issues are totally inadequate for precision CNC milling.
- The 4th rotary axis is hard wired. For full utility it should be fitted with an IP68 plug on the control cabinet so it can be removed. I have fitted one.
- The fourth rotary axis was not provided with a compatible tail stock. One was ordered but it is of exceptionally poor build quality and the centre height is not compatible with the rotary axis.
- There are no limit or homing switches on any of the axes. I have made some.
- My machine was ordered without the control cabinet. As a consequence it needs a sturdy bench to get the bed to a useful working height. It will also require machine guards to limit the spread of swarf and cutting fluid, and provide operator protection from potential projectiles.
- On initial shake-down I found that one of the X axis linear rail mounting bolts was not adequately secured (projecting proud of the rail). This is due to inadequate assembly. All rail mounting bolts were re-torqued.
- The spindle motor should only be operated with water cooling and should be run it at progressively increasing speeds over a period of at least 30 minutes. Failure to observe this may result in motor failure or reduced service life.
- The VFD parameters were not set correctly to show the spindle motor RPM. After obtaining a manual from the manufacturer (WMT did provide one eventually) I adjusted the parameters for the correct display. There is a discrepancy between the spindle speed reported by the VFD and the setting in Mach3 of about 2%. This has yet to be resolved (awaiting an optical tachometer for actual spindle speed measurement).
- The basic machine axis movement is quiet and smooth once the Mach3 paramaters are set appropriately with no apparent backlash or skipped steps. The spindle motor is also quiet and smooth with ample torque (certainly sufficient for cutting iron alloys). Initial surface cuts in aluminium have a beautiful surface finish that shows rainbow refraction from white light. Tolerances were measured to within 0.02 mm (X, Y only to date).
- There were numerous loose wiring terminations in the control cabinet and the wiring routing is far from optimal. I have removed about 10 m of wire from the loom and actually improved aspects of the sequencing with no functional loss.
- The control cabinet contains a redundant relay and contactor (which can be removed with increased wiring efficiency).
- The wiring is not colour coded. Everything is pretty much red and black with red to black junctions in the conduit. This makes servicing rather challenging.
Many of these issues are basic Quality Assurance (QA) matters for WMT to address. Getting these right would turn a capable basic CNC mill into an excellent machine that would compete with best in class.
Click here to link to Unboxing.