ELEKTOR FORUMS

Questions and answers on the ‘Profiler’ milling machine / Why? How? Who?

Lots of questions have been asked about the ‘Profiler’ milling machine in the four international Elektor forums. And lots of answers have been given too by users and Colinbus staff.
Yves Masquellier, though not himself a user of this machine, has valiantly tackled the considerable task of digesting the contents of some 800 messages in four different languages (!) in order to summarize here some essential points in a form that’s more digestible.

Disclaimer: none of the information contained in this FAQ is warranted by Elektor or Colinbus.

1. Communication with Colinbus/Franklin Industries
1a. Shipment tracking
According to numerous users, an e-mail is systematically sent out one or two days prior to despatch.

1b. Delivery delays
Information on extended delays in shipping orders was usually communicated through emails sent jointly by Colinbus and Elektor. Several customers did not receive these emails due to an inaccessible email box at their end.

1c. Supplier responsiveness
Buyers should not hesitate to report difficulties you experience to support@colinbus.com. Colinbus have a large number of queries to deal with daily.

1d. Documentation
To obtain manuals in English, all you have to do is request them from Colinbus (support@colinbus.com ).
Likewise, the control codes sent from the PC to the controller card are said to be available upon request from this same address, as there is nothing on the subject in the program help files or PDF guides.
You may need to make several requests as Colinbus really do have a large number of queries to deal with.

1e. Registration codes
They take rather a long time to get sent to you, and the procedure seems a bit unwieldy.
In the event of the need for a new registration code (machine crash, re-installation, etc.), simply apply to the address given above. Of course, this must only be used in cases of genuine need.

2. Mechanical construction
2a. General
Depending on your construction skills, the mechanical construction takes around ten to 20 hours. Very rarely, parts are either missing or replaced with others not described in the documentation.

2b. The Z-axis adjustment is tricky and sometimes involves dismantling several times, or even enlargement of the apertures to gain access to these settings.

2c. The drawing of the Z-axis limit switch is shown reversed in the assembly instructions.

2d. A suggested construction procedure is to build the electronics first so as to be able to operate each of the axes once it is assembled – screwed together but not tightened, to allow easier access to the adjusting elements.

2e. Built PROFILER is noisy
If the phenomenon occurs even when stopped, this is a quite common problem with stepper motors driven from a PWM if the servo loop is unstable.
If the problem only occurs when the motor is running, and the audio frequency is the same as the motor stepping frequency, you may also need to look at mechanical resonances. But in any event, the movements will never be silent – stepper motors ‘sing’ under the influence of the pulses transmitted and the PWM frequency (if this is within the audible range).

2f. Jamming (can cause step loss during use)
Jamming may be caused by ‘stiff spots’ caused by lack of lubrication, out-of-true runners or a shaft, build-up of foreign materials on these elements, areas of insufficient mechanical play, poor alignment, or non-concentric coupling between motor and shaft.
The cause is often screws that have been tightened too fully before alignment or distortion caused by over-tightening, as the components supplied are of industrial accuracy, and so significantly better than even careful manual workmanship makes it possible to achieve. So it’s very rare for them to be the cause of any problems experienced.

2g. AXIS by AXIS checking as you go is always best, and makes it easier to gain access to the settings.

2h. It’s invariably best to always try realignment first, virtually leaving the parts to take up their own positions without forcing them, and only then tightening screws after checking.
If precautions 7. and 8. prove fruitless, the simplest solution to solving a problem of eccentric coupling (and sometimes out-of-true shafts) is to make a ‘flexible’ coupling using a short piece of flexible tubing of suitable internal diameter (car hose, compressor air hose) and compressed air hose clips (less bulky than ordinary hose clips).
Don’t worry that these (relatively) flexible couplings will adversely affect your machining; they are widely used in amateur CNC.

2i. Accuracy and resolution
It’s unreasonable to expect this unit to achieve impossibly high performance – PROFILER is only meant to be a tool for ‘informed amateurs’.

3. Use / General
3a. Communication between the machine and ColiDrive is only enabled if, and only if, the machine has completely finished initializing.

3b. Alignment
Take care when drilling etched PCBs – if the layout was produced on a laser printer, which sometimes causes distortion, it is possible that the holes might not line up with the layout.
Films produced by inkjet seem to be less distorted.
Correct positioning of the board to be drilled has to be done manually. This is not a problem if you both engrave and drill on the same machine – though the supplier does make it clear that, even though this machine does allow engraving, it is not designed for this purpose.
However, if you regularly work with the same size of board, it’s easy to make a registering system. This solution can also be used if the engraving is carried out conscientiously at precise distances from the edges of the boards. Another very reliable registering method consists of manually drilling two very accurately positioned holes in the PCB in specially set aside areas, always the same, on all your layouts (for example, fixing holes, if you want them to serve some purpose).

3c. Fixing parts to be machined
Double-side tape is a solution that can be used for PCBs, but not for wood or balsa. What’s more, the flexing and inadequate flatness of the table cause problems. Double up the table (by gluing and screwing) so it doesn’t bend.
Then machine this new table surface using the milling machine itself to make sure it is flat
Parts that cannot be held with double-sided tape can be held using captive nuts fitted in advance into cavities drilled in this ‘reinforcing’ plate.

3d. DIY home-brew suction tables?
A vacuum cleaner won’t last long, as it needs to be ventilated, but unused holes have to be blocked up too, so there’s not enough airflow…
An old refrigerator compressor would be better. But the sideways forces exerted risk causing the piece being machined to slip.

3e. From drawing to engraving
For EAGLE it’s possible to use a ‘ULP script’ to format the EAGLE data so they can be used by COLILINER / COLIDRIVE. But future upgrades ought to allow operation without these intermediaries. GERBER files seem correct, but EXCELLON ones usually generate an error. The formats of these files have of course been subject to some major changes. The EAGLE 4.16r2-Standard version output format seem to be fine.
For technical drawings, all you have to do is create a generic LHPGL pseudo-printer and select ‘print to file’. This solution can be used for many drawing applications.
But watch out – COLIDRIVE does not recognize all incarnations of HPGL (amongst others, PU and PD won’t accept parameters).

4. The software supplied / General
4a. Colidrive
ColiDrive v 2.2.0.19 seems to be the most complete version at the time of writing (early July 2007), but not all HPGL data are interpreted correctly. It seems that some commands (Pen Up, Pen Down, etc.) don’t work when there are parameters.
Under W98, Colidrive only works line-by-line!
Windows 2000 with SP4 is said to work correctly, but there are said to be some problems with ATI or S3 cards.
To avoid crashing (usually caused by data saturation in the controller when handling big files), COLIDRIVE must be configured as follows: communication/setup/machine properties: on the second tab options/strategy set to ‘realtime communication’ instead of ‘transfer file to controller’.
If you want to send commands from a terminal, the communication between the PC and the controller card needs to be configured thus: 38400,8,N,1 – but apparently COLIDRIVE simply needs a vacant communication port with PROFILER connected and initialized.
Our Dutch friends are trying to make PROFILER work with an Open Source application. Another correspondent says that, in the light of the huge demand, it is possible that the applications running PROFILER might in the future accept the much more commonly used G-CODE.

5. Advice from the experts
5a. Miscellaneous
Here are some ideas provided by some forum contributors who’ve been working with CNC for some years:

The motor suggested in the article is not very robust and the spindle bearing risks wearing out very quickly. So you need to consider buying a proper milling spindle, like the ones on offer from Kress.
But watch out, as the fixing collar diameter is 43 mm and doesn’t fit the existing bracket. According to one user of this type of equipment, a 900 W motor seems a bit marginal for machining aluminium. As far as tools are concerned, you should use only tungsten-carbide bits, with a standard 3.2 mm shank (make sure you have suitable ‘collets’).

Milling and cutting-out may be performed using tungsten-carbide cutters up to 3 mm diameter, high-speed steel up to 8 mm if you have the right collet (in theory, supplied as standard).

Epoxy PCB can be milled using tungsten-carbide cutters only. Engraving can be done using a ‘spear’ type cutter, 22° for plastic and 35° for aluminium (distributors Welleman).

Feed rates are dependent on the size of the stepper motors, and above all, their drive voltage. A single feed rate of 5 mm/s in engraving requires 3.9 A stepper motors driven from at least 30 V.

Board drilling is usually performed from ‘Excellon’ files generated by most CAD applications.

PCB production by engraving the insulating paths between the track areas is of interest for prototyping, but you do need to find a suitable drawing program or else draw the insulation layout yourself – fairly easy with a little practice.

Any technical drawing program that allows exporting (or printing to a file in HPGL format) will allow you to design front panels and engrave text/images in 2D. Programs for creating PCB layouts need to permit the creation of the files for the track layout and the same files in EXCELLON format for the drilling.

For 3D use, the Ninos software performs very well and is not expensive – but is sadly not compatible with PROFILER. The same goes for GALAAD, more expensive, but possibly configurable? Of course there is DESKPROTO with a ‘LITE’ version, which does less than the aforementioned ones despite being twice the price of NINOS, but is recommended by the supplier of PROFILER (and so is presumably compatible).

5b. Adjusting the Z-axis origin
There are two methods for adjusting the origin, based on either a comparator or a sensor – the latter being suitable for initialization and calibration when changing tools, but not for checking in various places on the part to be machined. Not all PROFILER users will have access to a comparator or equivalent instrument, and tools for amateurs (drills, milling cutters, etc.) are not usually length-calibrated. Here’s a simpler method: a strip of thin paper placed on the table is trapped between the table and the tool by carefully lowering it by hand. The tool is then raised by about 0.1 mm, releasing the paper, and this is taken as the Z-axis origin.