cutting tool technology - tool geometry

Every machinists use cutting tools to make up a desired shape in a desired dimension, most of us are limited only on using it, but a little study will help to find the best method and tool to work on certain workpiece.
Most of these considerations involve cutting tool geometry :

• Lead angle is the approach angle of the cutting edge as it enters the workpiece. The lead angle controls the direction of the radial cutting force and axial cutting force.
• Rake angle is the incline of the top surface of the cutting edge that makes contact with the chip. The rake controls the degree of cutting forces and cutting edge strength.
• Clearance angle is the angled relief behind the cutting edge that eliminates interference between the cutting tool and the workpiece.
• Cutter diameter is the maximum flat surface a cutter will machine.
• Insert pitch is the distance between corresponding positions on one insert to the same position on the subsequent insert.
• Insert density is the number of inserts, or cutting edges, per inch of diameter.
• Hand of cut determines the cutter rotation direction. Milling cutters are designed to cut clockwise or counterclockwise.
• Mounting adaptation is determine by the type of machine spindle on which the rotating cutter is mounted. The method of mounting is a major factor in determining the rigidity and performance capability of the cutter.

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solidworks - viewing mates

I believe every 3d software user had at least several experience with assembly. It's easy to create, but sometimes it will take a significantly long time just to edit, when you decide to change the assembly structure, or when one of the component need to be replaced. The main cause is not in editing, but in finding the exact mate between two components that we need to edit. It might as well become a long painful journey for your tired eyes.

There are several possible solution for this,
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solidworks - delete

Most people know that you can delete lines from a sketch, or features from the Solidworks feature Manager, by pre-electing the object(s) and then simply hitting the DELETE key. But only few had known that over the last 4 years, the programmers have enhanced the intelligence behind the DELETE key, allowing it to react differently according to situations we're in.

Here's how DELETE will act when faced on several different circumstances :
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solidworks - using derived sketch

Derived sketch is one of a good feature that often overlooked. This tool derives a sketch from another sketch that belongs to the same part, or derives a sketch from another sketch in the same assembly! When you derive a sketch from an existing sketch, you are assured that the two sketches will retain the characteristics that they share in common. Every changes that you make to the original sketch are reflected in the derived sketch. Here I will show how to derive a sketch from a sketch in the same part:
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design guide 01 - design for assembly

It is very important for a machine designer to consider a lot of things when building a component. Whether it's able to be processed (design for manufacture); able to assembled easily (design for assembly); and even sometimes whether our machine can be repaired easily (design for maintenance).
Manufacturing process done in the machining workshop, the assembly would be done by assembly workshop. It is very important for a design engineer to know what's happening on the process. At least little by little information we gather will certainly help a lot for the next possible project.

What does it means to use "design for assembly" consideration? It means that every part is designed and modified well to ease the assembly process. As we all know, assembly is very important process that must be done correctly in order to obtain the desired shape (and often, includes obtaining functionality too)
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Failure Mode & Effects Analysis [FMEA]

FMEA is a procedure in product development and operations management for analysis of potential failure modes within a system for classification by the severity and likelihood of the failures. A successful FMEA activity helps a team to identify potential failure modes based on past experience with similar products or processes, enabling the team to design those failures out of the system with the minimum of effort and resource expenditure, thereby reducing development time and costs. It is widely used in manufacturing industries in various phases of the product life cycle and is now increasingly finding use in the service industry. Failure modes are any errors or defects in a process, design, or item, especially those that affect the customer, and can be potential or actual. Effects analysis refers to studying the consequences of those failures.
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weldment design 04 - product design rules

Welding may be imperfect and there's a million ways to overcome the distortion, but the best thing to do is considering the product's design carefully so that the effort on manufacturing is kept minimum
Just like plastic molding and sand casting, each welded product must be designed thoroughly according to the process they had to undergo. There is still some chance the distortion would happen, but on a straight line of procedures and a wise design, it wouldn't spend too much energy compared to a harshly designed ones.
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weldment design 03 - welding jigs

When you're talking about welding, the use of jigs, fixtures and positioners is usually desirable, for at least four reasons:
1. To minimize distortion caused by heat of welding.
2. To permit welding in a more convenient position.
3., To increase welding efficiency and productivity.
4. To minimize fit-up problems. With a welding jig or fixture, the components of a weldment can be assembled into accurate alignment and held securely in proper relationship and with correct fit-up during positioning and during welding so that all finished parts coming from the jig or fixture will be uniform.
For high quantity production, it is very economical to design and construct an accurate, durable jigs and fixtures.
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weldment design 02 - distortion

There was a time when the welding operator used to pick up his shield and electrode holder and commenced welding a job, beginning and finishing at any place. If the completed work became distorted, it was taken for granted that it could not be avoided. The impression was that all welding caused distortion, so there would be no point in worrying.
This was purely ignorance, because distortion can be controlled and minimized by approaching the job in a correct manner. Today, welded work is being completed with minimum or no distortion. For example, large machine beds are being fabricated out of rolled steel sections and plates and welded within a tolerance of 1.5 mm.

During welding, the base metal near the arc is heated to the melting point. A few centimeters away, the temperature of the base metal is substantially lower.
This sharp temperature differential causes non uniform expansion followed by base metal movement, or metal displacement if the parts being joined are restrained. Also, the expansion of the hotter base metal (i.e., which is nearer the welding arc) is subject to restraint, due to the resistance of comparatively colder metal away from the welding arc. The metal nearer the arc expands more than that away from the arc.
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weldment design 01 - welding joints

Before an arc can be struck on metal, the product must be designed to serve its purpose, the material chosen and the method of welding determined in more or less detail. The weldment design engineer must understand the principle of welding design :
1. Approach the redesign of previously cast, forged or riveted products as a new design, on the basis of the functions to be performed.
2. Use materials, where possible, which require the least in welding precautions and least skill.
3. Welding is a means to an end, but to the designer not an end in itself. Avoid extra and unnecessary joints by flanging, bending or rolling, and use of standard sections, stampings, small castings or forgings, wher ever necessary or advisable.
4. At least mentally review all the welding processes available and applicable to various parts of the design on the basis of material, thickness, form and quantity.
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tolerances - ISO tolerances

I've been working with machine for several years, and I learned that it is principally impossible to produce machine parts with absolute dimensional accuracy. In fact, it is not necessary or useful. It is quite sufficient that the actual dimension of the part is found between two limit dimensions and a permissible deviation is kept with production to ensure correct functioning of engineering products. The required level of accuracy of production of the given part is then given by the dimensional tolerance which is prescribed in the drawing. The production accuracy is prescribed with regards to the functionality of the product and to the economy of production as well.

A coupling of two parts creates a fit whose functional character is determined by differences of their dimensions before their coupling. 

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tolerances - surface finish

Mostly in design we are talking about fulfilling a component's specification. Whether it's about dimensional tolerance, shape, or maybe the desired surface finish. As we know before, surface finish and tolerance are closely linked. A component that are manufactured precisely, would have a good surface finish, on the other hand, rough surface finish usually hold a less precise dimension

The ability of a manufacturing operation to produce a specific surface roughness depends on many factors. For example, in end mill cutting, the final surface depends on the rotational speed of the end mill cutter, the velocity of the traverse, the rate of feed, the amount and type of lubrication at the point of cutting, and the mechanical properties of the piece being machined. A small change in any of the above factors can have a significant effect on the surface produced. There are 3 components defining the surface texture, that is : lay, surface roughness, & waviness

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motoGP early schedule

Yay, my only favorite game is back. This year might give a wonderful bike-to-bike fight between Valentino Rossi aka.The Doctor VS his ex teammate Jorge Lorenzo.

These last 2 years,I've been rooting for Valentino Rossi because of a simple reason, he rides Yamaha, and so do I. But this year, I might as well vote for Rossi again, not for much reason, only because I like the combination of Italian rider and Italian motorcycle. Not much to say again.

Date                                        Grand Prix (Circuit)
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tolerances - geometric tolerance

Geometric dimensioning and tolerancing (GD&T) is used to define the nominal (theoretically perfect) geometry of parts and assemblies, to define the allowable variation in form and possibly size of individual features, and to define the allowable variation between features. Dimensioning and tolerancing and geometric dimensioning and tolerancing specifications are used as follows:

• Dimensioning specifications define the nominal, as-modeled or as-intended geometry. One example is a basic dimension.
• Tolerancing specifications define the allowable variation for the form and possibly the size of individual features, and the allowable variation in orientation and location between features. Two examples are linear dimensions and feature control frames using a datum reference (both shown above).

There are some fundamental rules that need to be applied :

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list - gruesome torture device 02

Yeah, here comes the second part, another 10 torture device. Like what was stated in previous post. I'd like to try one of this on Mr.terrorist. of course they would not be given death. cause..well, death penalty is unavailable. Let them living in pain, in the other hand, i think is a brilliant choice.
These cruel instruments were commonly used throughout history to punish criminals, exert power over others and strike fear in the immoral and corrupt. Be sure to save that meal of yours for later; this is going to make your stomach churn
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list - gruesome torture device 01

I found this list accidentally when browsing. Yeah we all know, sometimes when we heard or see crime news in TV, such as murder and terrorism, it's hard to keep yourself calm. Death penalty, of course is not available in my country. But a simple prison punishment would be too easy for the evil-doers. So are there any other  possibilities?

Torture: it is an ancient practice that still goes on today. In the middle ages torture was used for punishment, interrogation, and deterrence. It is easy to consider ourselves more humane these days, but while some of the devices listed here would lead to death, we have, in modern times, mastered the ability of inflicting extreme pain for indefinite periods of time – something which is, perhaps, worse.

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gear technology - cycloid

The word Cycloid, with its adjective Cycloidal, is derived fromHypocycloid which describes the curve traced by a point on the circumference of a smaller circle rotating inside the circumference of a larger fixed circle

GEAR RATIO CALCULATION

The reduction rate of the cycloidal drive is obtained from the following formula, where P means the number of the ring gear pins and L is the number of pins on the cycloidal disc.

Ratio = (P - L) / L

Where P = Number of ring gear pins/rollers
             L = Number of lobes on a cycloidal disc

The method of operation is just like this :

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belt drive technology - basic belt types

A belt is a loop of flexible material used to link two or more rotating shafts mechanically. Belts may be used as a source of motion, to transmit powerefficiently, or to track relative movement. Belts are looped over pulleys. In a two pulley system, the belt can either drive the pulleys in the same direction, or the belt may be crossed, so that the direction of the shafts is opposite. As a source of motion, a conveyor belt is one application where the belt is adapted to continually carry a load between two points.

Belts are the cheapest utility for power transmission between shafts that may not be axially aligned. Power transmission is achieved by specially designed belts and pulleys. The demands on a belt drive transmission system are large and this has led to many variations on the theme. They run smoothly and with little noise, and cushion motor and bearings against load changes, albeit with less strength than gears or chains. However, improvements in belt engineering allow use of belts in systems that only formerly allowed chains or gears.
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bearing technology - rolling element bearing

A rolling-element bearing is a bearing which carries a load by placing round elements between the two pieces. The relative motion of the pieces causes the round elements to roll with very little rolling resistance and with little sliding.
Most rolling element bearings use cages to keep the balls separate. This reduces wear and friction, since it avoids the balls rubbing against each other as they roll, and precludes them from jamming
Even though some other kind of bearings are better in one or another specific attributes, many people think that it gives a pretty good tradeoff between cost, size, weight, capacity and durability. Therefore, it is one of the most widely used in machinery design
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bearing technology - plain bearing

A plain bearing, also known as a plane bearing, is the simplest type of bearing, comprising just a bearing surface and no rolling elements. Therefore the journal (i.e., the part of the shaft in contact with the bearing) slides over the bearing surface. The simplest example of a plain bearing is a shaft rotating in a hole. A simple linear bearing can be a pair of flat surfaces designed to allow motion; e.g., a drawer and the slides it rests on or the ways on the bed of a lathe.

Plain bearings, in general, are the least expensive type of bearing. They are also compact, light weight, and have a high load-carrying capacity. Read more

gear technology - harmonic drive

A Harmonic Drive (also known as "Strain Wave Gearing") is a special type of mechanical gear system that can improve certain characteristics compared to traditional gearing systems (such as Helical Gears or Planetary Gears). Basically it uses the flexibility of metal as the main component of mechanism

The mechanism is comprised of three components:
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gear technology - epicyclic/ planetary

Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer gears, or planet gears, revolving about a central, orsun gear. Typically, the planet gears are mounted on a movable arm or carrier which itself may rotate relative to the sun gear. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes with the planet gears.

The axes of all gears are usually parallel and what's more is that the sun, planet carrier and annulus axes are usually concentric
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belt drive technology - design and usage guideline

Unlike many old machines that employs gears for transmission method, Newer machines began to grow fond using belt drive, since it's cheaper, offers safety (belts will break on overload, unlike gears that take everything down with it) , easier to apply and it's easier for maintenance. One thing that we might forgot to highlight is that the belt drive efficiency actually depends a lot in heat factor.

Lifetime and performance in timing belts are greatly affected by the type of reinforcement employed. This internal component largely determines belt strength (modulus), creep, flex fatigue, and length variability (caused by humidity and temperature variation). Even though timing belt drives are generally considered to be very efficient, the operating temperatures they are exposed to can have a significant effect. Elastomers that run well hot will generally become much stiffer at low temperatures. This reduces drive efficiency as more energy is required to bend the belt around the pulleys. Elastomers that flex at lower temperatures are available, but they often wear too quickly at mid-range and elevated temperatures.
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solidworks - creating a forming tool

Not everyone interested in sheetmetal, but I've been looking at sheetmetal products likely such as stamping and curious how the SW users make the design. One thing should be noted is that whatever you bend in the sheetmetal feature, will be available in the flat pattern, so you only need to make the correct design, and you could see the flat pattern with just one click

The only thing that bothers me, is what will we do if we have customized stamping tool,that are not available in SW library? the answer was simple, we can make it and put it in our library
This is how you do it:
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