Minitech Mini-mill series User manual

Minitech CNC Mini-Mill

User’s Guide

Minitech Machinery Corporation

6050 Peachtree Parkway

Suite 240-205

Norcross GA 30092

P: 1-800-662-1760 P: 770-441-8525

F: 770-441-8526

www.minitech.com

MINITECH

CNC Mini-Mill User's Guide

TABLE OF CONTENTS

Preface

· Copyright 2

· Warranty 4

· FCC Statement 5

· Safety 6

· System Requirements 8

Installation

· Shipment Review 9

· Mounting the Machine 9

· Computer Interface Connection 10

· Controller/DCPower Supply Connections 11

· Stepper Motor Connection 13

Milling Basics

· Types of Work 14

· Spindle Mechanism 14

· Cutting Tools and Standard Accessories 14

· Operating Instructions 15

The CNC Milling Machine

· Parts of the machine 17

· Aligning the machine tool 18

Maintenance

· Work Site 30

· Cleaning 30

· Coupler Adjustment 30

· Lubrication 31

Service and Support

- Mechanical Drawings 33

MINITECH

CNC Mini-Mill User's Guide

Preface

Cop right

mechanical including photocopy recording or any information retrieval system without the

permission from the publisher. No patent liability is assumed with respect to the use of the

information contained herein. While every precaution has been taken in the preparation of this

guide the publisher and author assume no responsibilities for errors or omissions. Neither is

any liability assumed for damages resulting from the use of information contained herein.

All terms mentioned in this guide are known to be trademarks or device marks are listed

below. Minitech cannot attest to the accuracy of this information. Use of a term in this book

should not be regarded as affecting the validity of any trademark or service mark.

Minitech is a registered trademark of Minitech Machinery Corporation.

Mini-Mill/Pro Mini-Mill/3 Mini-Mill/GX Mini-Mill/2 are registered trademarks of Minitech

Machinery Corporation.

MINITECH

CNC Mini-Mill User's Guide

Warrant

Minitech Machinery Corporation warrants the Mini-Mill Desktop Manufacturing System to be

in good working order for a period of one year from the date of purchase from Minitech or an

authorized dealer. Should this product fail to be in "good working order" at any time during

the warranty period Minitech will at its option repair or replace the product at no additional

charge except as set forth below. This limited warranty does not include service to repair the

product resulting from misuse abuse or non-Minitech modifications to the product.

Limited warranty service may be obtained by registered owners by delivering the product to

an authorized dealer or Minitech with documentation of purchase date. If this product is

shipped the owner agrees to assume full risk of loss or damage in transit and prepay

shipping charges to the warranty service location.

For service contact and authorized dealer or write to Minitech at 6050 Peachtree Pky Ste.

240-205 Norcross Georgia 30092.

All expresses and implied warranties for this product including warranties of merchantability

and fitness for a particular purpose are limited in duration to one year from the date of

purchase and no warranties whether expressed or implied will apply after the this period.

If this product is not in "good working order" as warranted above the sole remedy shall be

repair or replacement as provided above. In no event will Minitech be liable for any damages

including lost profits lost savings or incidental or consequential damages arising out of the

use or inability to use such product even if Minitech or any authorized dealer has been

advised of the possibility of such damages or for any claim by any party other than the

original purchaser.

The foregoing warranty is in lieu of all other warranties expressed or implied including but

not limited to any implied warranty of merchantability fitness or adequacy for any particular

purpose or use. Minitech shall not be liable for any special incidental or consequential

damages whether in contract tort or otherwise. In no event shall Minitech be liable for

incidental consequential or special damages. Liability to third parties for bodily injury

including death relating to our performance or products delivered hereunder shall be

determined in accordance with applicable law and shall not exceed the payment if any

received by us for the product or service furnished. This warranty gives you specific legal

rights and you may also have other rights which vary from state to state.

Minitech warrants the product to function properly only when used Microsoft Windows 7

operating system. Minitech does not warrant the product to function properly in every

hardware/software environment. Furthermore Minitech does not guarantee or warrant that the

Mini-Mill will make or produce any specific part.

This warranty provides specific legal rights other rights may exist due to the varying State

laws.

MINITECH

CNC Mini-Mill User's Guide

Federal Communications Commission Statement

This equipment complies with the requirements in part 15.103(c) of FCC Rules for Test

Equipment. Operation of this equipment in a residential area may cause interference to radio

and TV reception requiring the operator to take whatever steps are necessary to correct the

interference. This unit is not for resale to the general public.

There is no guarantee that interference will not occur in a particular installation. If this

equipment does cause interference to radio of television reception which can be determined

by turning the equipment off and on the user is encouraged to try and correct the interference

by one or more of the following measures:

Reorient the receiving antenna.

Relocate the computer with respect to the receiver.

Move the computer away from the receiver.

Ensure that the expansion slot covers are in place when no board is installed.

Use properly shielded cables and connectors.

Plug the computer into a different outlet so that the computer and the receiver are on

different branch circuits.

If necessary the user should consult the dealer or an experienced radio/television technician

for additional suggestions. The user may find the following booklet prepared by the Federal

Communication Commission helpful: “How to Identify and Resolve Radio-TV Interference

Problems.” This booklet is available from the

US Government Printing Office Washington DC Stock no. 004-000-00345-4.

MINITECH

CNC Mini-Mill User's Guide

Safet

The most important lesson to learn is that of safety. Caution and safety must be considered at

all times when using the Mini-Mill as well as any machine tool. Although the Mini-Mill posses

only limited possibilities of creating injury users should learn and follow all safety rules any

time they operate the Mini-Mill.

Safet Rules:

1. Never Run A CNC Machine Unattended - CNC machines are potentially dangerous.

Untrained people must not operate the CNC machine. CNC machines are not toys.

Keep kids away. Never let the machine run unattended. Always wear safety goggles.

Unexpected machine movement can occur at any time. You are responsible for the

safety of yourself and others. You are working at your own risk.

2. Always Wear Safety Glasses - foresight is better than no sight! The Operation of any

power tool can result in foreign objects being thrown into the eyes which can result in

severe eye damage. Always wear safety glasses or eye shields before commencing

power tool operation. For the best protection we recommend wide vision safety mask.

and standard safety glasses.

3. Know Your Mini-Mill Machine - Read the owner's manual carefully. Learn its application

and limitations as well as the specific potential hazards.

4. Ground All Power Connections - All the AC plugs are equipped with a three pronged

plug. Make certain the receptacle is properly grounded.

5. Keep Guards In Place - Never remove the safety shield. Use it for the protection of

flying debris.

6. Remove Adjusting Keys And Wrenches - Form a habit of checking to see that keys and

adjusting wrenches are removed from the spindle and machine prior to turning the

machine on.

7. Keep Work Area Clean - Cluttered areas and benches invite accidents.

8. Avoid Dangerous Environments - Do not use power tools in damp or wet areas. Keep

area well illuminated.

9. Keep Children Away - All visitors should be kept a safe distance from the machine

area.

10. Make Work Area Child Proof - with locks master cutoff switches.

11. Do Not Force Tool - Do not force tool or attachment to do a job it was not designed for.

12. Use The Right Tools - Do not force tool or attachment to do a job it was not designed

for.

13. Wear Proper Apparel - Avoid loose clothing or jewelry that could get caught in the

moving parts of the machine and spindle mechanism. Wear protective head gear to

keep long hair away from moving parts.

14. Use Safety Glasses - Also use a dust mask if cutting operation is dusty

MINITECH

CNC Mini-Mill User's Guide

15. Secure Work - Use clamps or a vise to hold work. Do not you your hands to hold work

down.

16. Do Not Touch Machine When It Is On - Avoid touching any part of the machine while it

is operating. If the proper settings are made and the work is fastened properly there is

no need to touch the machine.

17. Maintain Tools In Top Condition - Keep tools sharp and clean for best results and

safest performance. Follow instructions for lubricating and changing accessories.

18. Disconnect Tools - before servicing and when changing accessories such as end mills

and cutters.

19. Avoid Accidental Starting - Make sure spindle switch is off before plugging in power

cord.

20. Use Recommended Accessories - Consult the instruction guide. Use of improper

accessories may be hazardous.

21. Check That All Holding Locking And Driving Devices Are Tightened - At the same

time be careful not to over-tighten these adjustments. They should be just tight

enough to do the job. Over-tightening may damage threads or wrap parts thereby

reducing accuracy and effectiveness.

22. Be Aware Of These Safety Precautions - and use these as a basis for your safety

protection. Implement your own safety rules in conjunction with these.

MINITECH

CNC Mini-Mill User's Guide

S stem Requirements

Prior to setting up your Mini-Mill make sure you have the proper requirements for the system.

It is also recommended that you first setup your computer system and software prior to

installing the machine. The minimum requirements for the Mini-Mill are:

Processor 1Ghz CPU

Memory 512

USB 1.1 or 2.0

Operating System Windows 2000 Windows XP Windows Vista or Windows 7

Software Mach3 Version R3.042.040 with Minitech Screen Sets

MINITECH

CNC Mini-Mill User's Guide

Installation

Shipment Review

You should review your Minitech shipment to see how many packages you received. To do

this check first with the Ship List located on the outside of box number one. If there is only

one box then it will be marked as 1/1 or 1 of 1 box.

Review the ship list carefully. The ship list provides you with the contents of each box and the

items ordered. Although you may not be completely familiar with all the items it is important

that you become introduced to items as they become unpacked.

If you are uncertain of what some of the items are do not worry. Simply call Minitech on our

toll-fee telephone number if you need any assistance or would like further information on

setting-up your system. We are happy to assist you.

To open the shipment follow the instructions below.

1. Carefully open the crate containing your Mini-Mill machine. This should be a large wooden

crate.

2. As you open the box notice the four mounting screws that attach the mill to the plywood base.

This secures the machine during shipping and is not need for operating the machine.

Therefore remove the four mounting screws from the base prior to attempting to remove the

machine from the box. Note: Some Mini-Mills have only mounting straps that need to be

removed.

3. Once the machine is unsecured from the plywood base it can then be pulled-out of the box

and placed on a bench or desktop. Do not lift machine by the stepper motors. This should be

within a five-foot distance from the computer system you want to control your new Mini-Mill.

Remove any items from your bench that may interfere with the operations of the mill or items

that may become entangled with the spindle mechanism.

4. Open all other boxes (if any) and inspect their contents with the ship list provided.

Mounting the Machine

Use your discretion to mount the machine to a solid surface. We recommend mounting the

Mini-Mill to a table surface for maximum stability and machining accuracy. The four mounting

holes in the chip tray provide an excellent way to bolt the machine to a mounting surface. The

Mini-Mill can be mounted to a machined surface or pre-finished board using four machine

bolts and rubber washers and nuts available through local hardware stores.

This arrangement will give the Mini-Mill a stable and secure platform for operating the

machine. The rubber washers will help in reducing noise created by the spindle motor

spindle and cutting surface. The better the foundation the less vibration will occur and the

better the machine will perform.

MINITECH

CNC Mini-Mill User's Guide

Computer Interface Connection

The Mini-Mill is controlled by a PC based computer. This means that the signals used to

control the table movements and other operations are all controlled by the computer. The

Mini-Mill system is supplied with a USB cable with the same type of connector at each end. It

is a standard cable which can be purchased at any computer outlet if you should misplace

this item.

Do not attempt to connect the interface cable while either the computer or Mini-Mill is

powered on. This may cause electronic failure to These electronic components. For your

safety and the integrity of the equipment turn all devices off prior to making any interface

connection.

Setup the computer to be used with the machine and install the controller software. Refer to

the CNC Stepper Motor Control Box CS5SA8-1 manual for installation instructions. If at

anytime you experience inconsistent table motions or no table motions at all check this cable

to make sure it is properly installed.

MINITECH

CNC Mini-Mill User's Guide

Controller Connections

Follow these instructions to make the cable connections for USB interfacing AC power in

motor and sensors

The Mini-Mill's CNC Stepper Motor Control Box (Controller) outputs DC current and is

supplied by AC current coming in from a 110 outlet (international 220 VAC). The power cord is

equipped with a 3-prong ground plug that must be connected to a properly grounded

receptacle for your safety. If an electrical failure occurs the grounded plug and receptacle will

help protect the user from electrical shock. Only use a properly grounded outlet when running

your Mini-Mill.

NOTE: The power supply must be connected to a properly grounded receptacle for your

safety

NOTE: Do not attempt to make any connections to the controller while the power supply is

plugged in or turned on. Unplug the power supply and make sure the power switch is in the

off (down) position.

1. Connect the supplied AC cable. One end goes to the wall outlet the other goes into

the receptacle marked AC IN.

2. Connect the interface cable from one of the computer's USB ports to the back of the

controller marked USB.

3. Stepper Motor Cables - These get connected to each one of the stepper motors. Each

cable corresponds to a motor; match the X to the X motor Y to Y etc. The other end

gets connected to the Controller – marked X Y Z A

4. The sensor cable gets connected to the RJ45 marked SENSORS

5. The other RJ45 marked Spindle will be covered below

MINITECH

CNC Mini-Mill User's Guide

Front

Power Switch - This is on the right side of the controller box. On is in the up position off is

down. A light illuminates when power is on.

Emergency Stop - This cuts the power to the stepper motors in case of a failure. Press this

when you want the stepper motors to shut off.

BACK

AC IN - Connect the power cord from your wall outlet into this connector. It supplies the AC

power for the controller.

MINITECH

CNC Mini-Mill User's Guide

Computer Interface - Connect the parallel cable from your computer into this connections

Stepper Motor Connections

Stepper Motor Cables - These get connected to each one of the stepper motors. Each cable

corresponds to a motor; match the X to the X motor Y to Y etc.

The Mini-Mill has three stepper motors that control the movements of each table. Each

stepper motor has a cable that leads from the motor's case to the controller box.

NOTE:Make sure all power devices including the computer controller and spindle are turned

off prior to making the stepper motor connections.

Take the lead of each motor and find the corresponding outlet. Snap the connector into the

corresponding connector.

NOTE: The stepper motor connections are important. To assure you have made the right

connections review the following diagram. Make sure the correct axis is connected to the

corresponding axis port on the controller box.

Problem Solving: To check to see if AC power is getting to the controller power supply turn it

on and the red light switch should come on. If it does not check the fuse on the back side of

the power supply. If it is blown replace it with the same power rating. Do not attempt to

operate the power supply with out the properly installed fuse.

Problem Solving: Check DC power. There are two ways to see if DC power is getting to your

Mini-Mill. One you will hear and feel a fan come on when the power supply is turned on. If no

fan check connections and retry. Second when the power is turned on the motors should be

torqued and it becomes difficult to turn the lead screws by hand. If the lead screws are easy

to turn (with the power on) you are not getting power to the interface card and the stepper

motors.

MINITECH

CNC Mini-Mill User's Guide

Milling Basics

The Mini-Mill's three table motions are classified as X Y and Z axes and are standard to

most industrial operations. Additional CNC programming terminology is explained in the CNC

User's Guide. If you are not familiar with CNC program and controls it is recommended that

you study this prior to using the Mini-Mill system.

T pes of Work

There are three basic types of work the Mini-Mill can perform; milling drilling and boring.

Additional work with accessory items such as our Mini-Rotary Table is available for attaining

machining of cylindrical objects.

Milling on the CNC Mini-Mill is usually accomplished with end-mills. These are the cutters

designed to cut with both the sides and the end.

Drilling is accomplished by special CNC commands given to the mill. It is also recommended

that center drills be used prior to drilling to achieve the maximum degree of accuracy.

Spindle Mechanism

It is important to note that you can overload the spindle motor. The many variables involved in

machining such as materials being machined size and shape of end mill sharpness can

lead only to one rule to follow .... Common Sense!

Heavy cuts at low RPM will make the motor run hotter than light cuts at high RPMs. In normal

operations the spindle motor will run warm to the touch but not hot. This does not mean your

machine can not run at low RPMs but only that the load put on the motor must be considered

in each setup and operation of the machine.

Cutting Tools and Standard Accessories

End Mills

End mills are the standard vertical mill cutting tools. Your Mini-Mill was designed to employ

miniature series end mills having 1/8" 3/16" or 1/4" shank sizes. A 3/8" end mill holder is

also available. We recommend using 2-flute single-end high speed steel end mills. The solid

carbide tools are more expensive

and the cutting edges will chip unless used properly. End mills may be purchased from

industrial machine shop outlets or catalogs. As smaller diameter cutters (less than 1/8") are

MINITECH

CNC Mini-Mill User's Guide

quite fragile the largest diameter cutter possible for the job requirements should be

employed. Be certain that the RPM is appropriate before attempting to remove any material.

An end mill can be instantly damaged if a cut is attempted at excessive RPM.

There are no firm rules other than common sense in determining the depth of cut. Commence

with very light cuts and increase depth of cut until satisfactory cuts are achieved.

Note that end mills should not be used for drilling; however they may be employed to enlarge

an existing hole.

Collet Set

The main purpose of the collet set is to hold end mills securely. The spindle nose has an

internal Morse No. 1 taper which closes the collet as the Draw bolt is tightened. Morse tapers

are approximately 5/8" per foot and are self locking. Therefore to loosen a collet the draw

bolt must be loosened a few turns and taped with a hammer to release.

Hold Down Provisions

Some CNC Mini-Mills are supplied with a set of V-block clamps. This secures most materials

to the surface of the mill's table top. The table top supports several 1/4-20 tapped holes

separated at one inch centers for modular placement of parts. For additional hold-downs it

may be necessary to purchase a small manual vise. This can be fitted with bolts to secure it

to the table.

Mini-Mill Operating Instructions

Minitech machines are among the finest tools that can be purchased for the price along with

offering the degree of precision found in machines costing several times more they are

capable of very precise and exacting work when properly employed. In short we feel that this

is the best possible product in its price range on the market today.

Follow these guidelines prior to operating your Mini-Mill:

1. The Mini-Mill is a small light duty machine which should not be used for removing large

amounts of material. For efficiency select a piece of stock that is close to the finished size

as possible.

2. Stresses on any mill are high when cutting most materials. These stresses cause most

machines to be constantly adjusted for gib tightness and backlash. The Mini-Mill does not

have these adjustments to make because of its dual linear shaft design. It also supports a

MINITECH

CNC Mini-Mill User's Guide

zero-backlash lead screw nut that does not need adjusting.

3. End mills must be true and be sharp. Holding end mills in a drill chuck is a poor practice.

Use collets instead.

4. For accurate setup you should have and know how to use a dial indicator. The trueness of

the spindle can be more accurately attained which results in more accurate work.

5. Often more time is spent on designing part programs and setup than on actual machine

time.

6. Always plan on having a start reference point from which to begin the job.

7. A good rule to follow is: if the tool chatters reduce the spindle speed and increase the feed

rate.

8. It takes a long time to accumulate the knowledge tools and fixtures required for many

different types of applications. Try not to become discouraged by starting with a job that is

too complex or by using materials that are extremely difficult to machine.

9. Test your part programs and work in prototyping material first. This will reduce the cost of

materials and allow you to practice machining. You can even test your programs without

cutting anything just let the machine go through the motions - cutting air.

MINITECH

CNC Mini-Mill User's Guide

The CNC Milling Machine

Figure 6: Mini-Mill 3

Parts of the Machine

Figure 6 is a photograph of the Minitech Mini-Mill 3. This particular model is a 4-axis vertical

CNC milling machine. There are three linear axis; X Y and Z; and one is rotational A. The

figure illustrates the machine axis and their direction of movement.

MINITECH

CNC Mini-Mill User's Guide

Aligning the Machine Tool

The following processes are recommended for advanced users only. If these adjustments

need to be made please contact your authorized dealer and a qualified service technician can

perform this service. These machines go through a quality control process before delivery and

these tests have already been performed.

Minitech nor its affiliates will be responsible for damage or injury done from use of these

processes or use of the machine.

Alignment Tools

Ideally all parts of a machine are perfectly uniform square flat and perpendicular or parallel

to one another. The reality is that there are tolerances to which the machine is true. A

machine can not create parts anymore accurate or precise than the accuracy or precision of

the machine itself. So it is important that the machine be adjusted properly to obtain

dimensionally accurate parts repeatedly. In order to do these adjustments and understand the

nuances of your machine you will need a set of tools. The list of recommended tools is below.

Dial test indicator with 0.0005” increments

A steel parallel bar that is accurate and uniform

A steel round bar with center drill hole in end that is accurate and uniform

Hex key set

Shim material (rolling papers)

A micrometer with 0.0005” increments

With careful attention to detail and the processes illustrated below you will be able to use the

mill to produce parts to tolerances of ~0.001”.

X/Y Table Alignment Flatness

The first step is to test the flatness of the machine table. The table is not perfectly flat. It is

good to know how flat it is so when mounting parts on the table you can make adjustments.

This will become important when mounting material or a fixture like a tail stock or rotary axis

on the table. In the pictures the red arrows indicate the direction the tool is moving relative to

the table. Understand that the tool never moves except up and down but the position of the

machine is always referred to by the position of the tool tip. To test the flatness of the table the

process is as follows.

MINITECH

CNC Mini-Mill User's Guide

1. Mount the dial test indicator in the spindle.

2. Jog the machine so the indicator is at the end of the table and lower the Z-axis so that

the ever of the dial test indicator touches the table.

3. 3. Once the ball of the lever touches the table make sure the needle moves at least a

few thousands. Then zero the indicator.

4. 4. Jog the X-axis to the left.

5. As the table moves underneath the indicator note the change in height on the indicator.

6. You will see that the table is pretty flat but not perfect.

7. 7. Move the Y-axis so that the tool is at the front of table set the indicator then move

the Y-axis and note changes in height.

Figure 8: Measuring table flatness across x and y

Alignment

There are six degrees of freedom that need to be

accounted for in aligning the machine table. They are the

pitch roll and yaw. Pitch is the how perpendicular the

machine bed is along the X-axis relative to the Z-axis.

Roll is how perpendicular the machine bed is along the Y-

axis relative to the z axis. Yaw is how perpendicular the

machine bed is along the x-axis relative to the y-axis.

Adjusting the pitch and roll is possible by screw tightening

MINITECH

CNC Mini-Mill User's Guide

methods and shimming. Adjusting the yaw of the machine is not necessary and beyond the

scope of the manual. The methods of measuring the pitch and roll are described below.

1. Place a precision parallel bar on the table. (pictured bar is flat/parallel to .0001”over 6”)

2. Run the dial test indicator along the parallel bar noting the change in pitch.

3. Do the same for the roll.

Figure 9: Measuring pitch and roll of table.

4. If for any reason the table must be removed or replaced it is important the table is

properly installed to insure accuracy. This will require the loosening and/or removal of

sixteen slide screws and the four screws which attach the table to the lead nut. Figure

10a shows the lead nut screws. Figure 10b shows the area to place the shim.

Minitech Mini-Mill Series User manual

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