Rokoko offers a full performance motion capture system. We have our motion capture suit, the Smartsuit Pro - our new hand and finger tracking system, the Smartgloves and facial capture. We offer our own software, Rokoko Studio and Rokoko Studio Live, with native integrations with the most popular animation engines. Mokoko is a independent coffee shop and bakery based in Bath and Bristol, they currently have 3 shops, one in Bristol with a in house kitchen and 2 in Bath. With growing success and recognition of the brand locally, Mokoko have chosen to move into the coffee roasting market and develop their own distinctive Mokoko coffee brand, for both B2C.
Defects in casting
Foundry industry in developing countries suffer from many casting defects . Even in complete controlled process , defects in casting are observed and hence casting process is also know as process of uncertainty .
There is a various reason or sources which is responsible for the defects in the cast metal. Here we will learn more about different major types of casting defects.
Types:-
Casting defects can be classified as follows
- Filling related defects
- Shape related defects
- Thermal defects
- Defects by appearance
Filling Related defects:-
Blow holes:-
- It is a kind of cavities defects, which is divided into pinhole and subsurface blowhole.
- Pinhole is very tiny or small hole and subsurface blowhole only can be seen after machining.
- When gases entrapped by solidifying metal on the surface of the casting , which result in a rounded or oval blowhole as a cavity.
- This defects nearly always located in the cope part of the mold in poorly vented pockets and undercuts.
Causes:-
Resin-bonded sand
- High release of excessive release of gas from core
- Excessive moisture absorption by the cores
- Low gas permeability of the core sand
Clay-bonded sand
- Moisture content of the sand high
- Low gas permeability of the sand
- High sand temperature
- High bentonite content
Remedies:-
Resin-bonded sand
- Improve core venting and provide venting channels ,ensure core prints are free of dressing.
- Reduce amount of gas or use slow reacting binders.
- Apply dressing to cores,the slowing down the rate of heating and reducing gas pressure.
- Dry out cores and store dry , thus reducing absorption of water and reducing gas pressure.
Clay bonded sand
- Try to reduce moisture content of sand , improve conditioning of the sand
- Improve gas permeability .
- Reduce temperature of sand use sand cooler if necessary .
- Reduce bentonite content , use bentonite with a high montmorillonite content , high specific binding capacity and good thermal stability.
- Use low reacting lustrous carbon producer
Sand Burning:-
Burning on defects also called as sand burning, which include chemical burn –on , and metal penetration. These defects occur to a great extent in the case of thick- walled casting and at high temperature.
Causes:-
Clay- Bonded sand Plugin alliance free.
- Low lustrous carbon content
- Proportion of low melting point substance too high
Molding plant
- Uneven mold compaction
Gating and pouring practice
- High temperature of liquid metal
- Uneven distribution of in flowing metal with resultant over heating
Remedies:-
Clay-bonded sand
- Increases proportion of lustrous carbon producer, which result in positive separation between mold and metal.
- Use pure silica sands
Molding plant
- Ensure uniform heat compaction and try to increase heat removal from the molds.
Gating and pouring practice
- Even out incoming metal flow
- Reduce pouring rate
- Reduce liquid metal temperature
Sand inclusion
Sand inclusion are also called as scab or blacking scab and it look like small or middle holes with sand grains in the internal or on the surface of casting. This casting defect formed during abrasion of the mold surface by the metal flowing past and the associated thermo-mechanical stresses.
Causes
Molding plant
- Break up of mold section during stripping of patterns
- Uneven compaction of molds
Clay-bonded sand
- Low compatibility
- Very low bentonite content
- High inert material content
- High lump content
- High content of lustrous carbon producer
Resin- bonded sand
- Low core strength
- Excessive core mismatching
Gating and pouring practice
- High pouring rate
- Ladle too high above pouring basin
- High pouring time
Remedies
Molding plant
- Check mold for pressure mark if require add pressure pads
- Carefully blow out mold cavities
- Increase pattern tapers and radii, improve pattern plates
- Ensure uniform mold compaction , avoid over compacted sections.
Clay bonded sand
- Raise compact ability and plasticity of the sand
- Increase bentonite content.
- Reduce inert dust content
Resin bonded sand
- Increases the strength of the core, use greater proportion of binder.
- Avoid core mismatching
Gating and pouring practice
- Avoid high pouring rates and impact of metal stream against mold walls.
- Improve distribution of gates.
Cold lap or cold shut
Cold shut also called as cold shut .It is crack with round edges.Cold lap is because of low melting temperature or poor gating system.
When the metal is unable to fill the mold cavity completely and thus leaving unfilled portion called misrun.
Causes
- Lack of fluidity in molten metal
- Faulty design
- Faulty gating
Remedies
- Adjust proper pouring temperature
- Modify design
- Modify gating system
Misrun
When the molten metal is unable to fill the mold cavity completely or molten metal solidify before filling the mold cavity completely and leave a space in mold called misrun.
Debitare pal melaminat. Causes:-
- Lack of fluidity in molten metal
- Wrong design and wrong gating
Remedies
- Maintain proper pouring temperature
- Modify design and gating system
Gas porosity
Gas porosity is nothing but the formation of air bubbles within the casting or pin hole on the surface of the casting.
When the molten metal start filling the cavity , before that air is present in the cavity .When we poured molten metal air start compressing as more and more metal streams in to the cavity and the pressure rises.
When cavity full it becomes dispersed as small sphere of high pressure air. The swirling flow can cause them to become elongated.
Causes:-
- Low metal pouring temperature
- Low metal fluidity
- Slow pouring
- Slag on metal surface
- Interruption to pouring during filling of the mold
- Thin metal section
- High gas pressure in the mold arising from molding material having high moisture
Remedies
- Increase metal pouring temperature
- Modify metal composition to improve fluidity
- Remove slag from the metal surface
- Reduce gas pressure in the mold by appropriate adjustment to molding material properties and ensuring.
- Modify casting design and avoid thin section
- Use insulating coating and ensure that molds are adequately pre-heated.
Shape defects
Mismatch defects
Mismatch in casting is common defect, when casting does not match at the parting line or improper alignment of upper and lower portion of the casting.
Causes:-
- When cope and drag parts of the mold not remaining in their proper position
- Misalignment of flask
Remedies
- Use proper closing pins and molding boxes
- Check pattern mounting on match plate and rectify , correct dowels
Distortion or wrap
Distortion due to wrap age is known as warp defect.
Causes:-
- It occur time in a casting that partially or completely liberates residual stress.
Remedies
- Common practice in iron casting is normalizing heat treatment to remove residual stress.
Flash defect:-
Its also known as flashing, fins or burns ,it also defined as when unwanted or excess material is attached to a molded or cast product .
Mokoko Crack Cocaine
Causes
- Improper clamping of the flask can also creak flash defects
- When part of the die have insufficient strength
- Damage die component and die faces
- Cavities offset from center of platen
- Wear or damage in toggle mechanism
- Hydraulic valve or seal leak
Remedies
- Reassembling the molds and core and there should be a enough weight on the top part of the mold so that the two parts fit together tightly.
Cracks and tears
Cracks can be seen with the naked eyes and it appears in casting from a number of reason.
Causes
- When molten metal does not have sufficient strength to resist tensile force during solidification.
- It mostly caused by poor mold design.
- because of thermal imbalance in the die
- undercut or damage in the die cavities
Remedies
- try to reduce pouring temperature
- provide feeders
- give sufficient cooling time
- reduce sharp corners
Shrinkage
This defects occur when filling material is not available for shrinkage as the metal start solidify.
This defects again split into two parts :-
1)open shrinkage defects
2) closed shrinkage defects
Open shrinkage defects:-
This defect is open to atmosphere and easier to notice ,they can be caved surface or pipes that enter into the surface of the casting.
Closed shrinkage defects:-
This type of defects are difficult to spot, and they are hidden within the casting and causing structural impurities. Under this defects isolated pool of liquid metal is form inside solidified metal which are called hot spots and shrinkage defects usually forms at the top of the hot spots.
Causes:-
- When density of die casting alloy in liquid state is less than its density in solid state. There for when alloy change its phase from liquid states to solid state, it always shrinks in size.
- When pouring temperature is too high
Remedies
- To avoid shrinkage porosity ensures that liquid metal under pressure is continue to flow into the voids as they form.
- Apply principle of directional solidification in mold design.
Sink Mark
Sink mark are unintended depression on the surface of molded part ,this marks are very small and often quite visible because they reflect light in different directions to the part.
Sink mark occur when there is a thicker section of plastic compared to the general wall thickness. The Greater the difference in thickness, the more shrinkage is concern.
Causes:-
- This marks formed mostly because of thermal contraction or shrinkage during cooling.
- After the material on the outside has cooled and solidified, the core material starts to cool . its shrinkage pulls the surface of the main wall inward, causing a sink mark.
- If the skin is rigid enough, deformation of the skin may be replaced by formation of a void in the core.
- High volumetric shrinkage
- Insufficient material compensation
- Short cooling time
Remedies
- Optimize the runner system design
- Try to use different material
- Try to reduce volumetric shrinkage
- Change the part geometry
- Optimize packing profile and control the packing pressure
Defect by appearance
Metallic projection
- Metallic projection also called as joint flash or fins and it occur at the parting of the mold or whenever two elements of the mold intersect.
Causes
- Because of incorrect assembling of mold and cores
- Insufficient weight of the mold clamping of the flask may produce the fins.
- Blowholes and pinholes are produced because of gas entrapped in the metal during the course of solidification.
Remedies
- Correct the assembling of mold and cores
- Provide sufficient weight on the top part of the mold so that the two parts fit together tightly.
- Make adequate provision for evacuation of air and gas from the mold cavity.
Discontinuities
Discontinuities are also called as hot crack and hot tears and it is the formation of shrinkage crack during the solidification of weld metal.
When metal in liquid condition it is weak and the residual stress or tensile stress in the material causes the casting fails as the liquid metal cools down. The failure of casting in this case is looks like cracks and its called as hot tear or hot cracking.
Causes:-
- Damage to the casting while hot due to rough handling
- Improper mold design
Remedies
- Care in handling mold while it is still hot
- Proper mold design can eliminate this defects
- Elimination of the tensile stress from the material of the casting
Incomplete casting
Incomplete casting is common casting defect it occur when molten metal is unable to fill the extremist of the mold and its also called partially complete casting.
Causes :-
- Insufficient alloy is used
- High viscosity of fused metal or metal is not so hot and so metal is not able to enter thin parts of mold.
- Casting pressure is low
- Insufficient venting of the mold or improper burnout
Remedies
- Have sufficient metal in the ladle to fill the mold,check the gating system.
- Increase temperature of the alloy and rise liquids temperature
- Decrease the viscosity and surface temperature of the alloy
Incorrect dimension or shape
When geometry of metal casting is incorrect this could be due to unpredicted contractions in the part during solidification or this occur when the metal does not shrink properly .When the cast sets, it is the wrong size or it is warped or bent.
Causes
- When rigidity of the pattern is insufficient to withstand the ramming pressure applied to the sand, this result in an elastic deformation of the pattern and a corresponding , permanent deformation of the mold cavity .
Remedies
- Assure adequate rigidity of patterns and patterns plates, especially when squeeze pressure are being increased .
Defective surface
When the liquid metal is leak out of the mold and the defect appears as lines which trace the flow of the streams of liquid metal. This defects are also called as flow marks and they are easy to remove and always reveal a buckle underneath.
Causes
- Oxide film which make cottage at the surface , partially making the path of molten metal flow from the mold.
Remedies
- Increase the liquid metal temperature
- Modify the gate size
- Reduce the pouring temperature
Rat tail and buckles
When the temperature of molten metal is too high it caused the expansion of a thin outer layer of molding sand on the surface of the mold cavity.
Causes
- Caused by compression failure of the skin of the mold cavity because of excessive heat in molten metal.
- A buckle is a more severe failure of the sand surface under compression.
Remedies
- Provide proper expansion to mold to avoid compression layer.
Author:-
Gopinath Murthi
I'm so excited to share this new series with you. Business Story is about small businesses and the people behind them. I love getting a behind the scenes look into a creative business and see what makes it tick. I'm sure you do, too. So, brew yourself a cup of tea or coffee, sit back, and enjoy. Today, I'd like you to meet Mari, the designer behind Mokoko, a small leather goods brand with a big vision.
Tell us a little bit about you, the person behind Mokoko. Where are you from? What's your background? Maybe a little something that doesn't meet the eye.
My name is Mari Maripuu I was born in the university town of Tartu and later lived years in Saaremaa (Estonia's biggest island) before coming to the Estonian Academy of Arts (EKA) in Tallinn. My initial plan was to study biochemistry and later specialize on viruses, but with my exam results it would have been impossible to study it for free. My family was not financially secured and I did not want to get a loan from the bank.
My other interest was in fine bookbinding. I have gone to art schools all my life, but the one in Kuressaare had the biggest impact on me. Piret Männa introduced me to bookbinding and leather craft. Teachers have the ability to change lives. So, at the last minute I decided to take the entrance exams to EKA Leather Art, Accessories Design and Bookbinding department, and I got accepted. I decided to first study this for free and later pay for my biochemistry studies. But, by the time of my BA graduation I saw millions of possibilities what to do with design, so I decided to continue my studies in the Product Design (MA) department. So, basically I am still able to work with viruses, but from a different angle – machinery design, process design, design solutions for improving hygiene so that people would not spread viruses or get ill.
I love your slogan 'Buy nothing you do not need'. One would think that being an independent designer, you'd want more sales rather than encouraging people not to buy. How did you come up with this tagline and how does is translate into what you make?
The slogan I use on one of the wallet designs is actually 'buy nothing', but to make it not so radical I specified it a bit for my overall brand. I was a little bit afraid that it could be interpreted in different ways.
When the slogan is on the product and the person goes shopping he might get the impulse to (maybe) buy nothing at all from that shop. So, when the slogan is on the daily-used wallet, the person might buy less. Of course, if they really-really need or want something they will get it anyway. But, having this small reminder in your wallet might make the purchasing decision more thought through and this is what I'm after. Because really, you don't need that much stuff.
Being independent allows me to try things that are not that traditional and carry the values I believe in. There's one book (Gabriel Zaid, So Many Books: Reading and Publishing in an Age of Abundance, 2003) that I had to read for an bookbinding exhibition last year and there it was said that if you give someone a book, you actually give them the obligation to read it. When you buy something, you will get the obligation to use it. And when you are not using it, you are constantly reminded that you should take time to use it and it gets you even more stressed. So, mentally, it is better to have less.
What does a typical day look like in the Mokoko studio?
At the moment most days of the week I am at the uni or working on other projects, so I probably go there 4x a week to make stuff that is needed. I am not alone in the studio, I have two other leather designers there, we split the expenses and they rent some machines and equipment from me. There are lots of different machines and tools needed to do this work, so it's best to be friendly and share. We use this space mostly only as a workshop, not as a open designer studio. It's very ascetic, but beautiful things come out of it.
It's really typical that I start the day in the studio with turning on the radio – I enjoy listening to talk-shows, on any topic. At the moment, I do everything myself because my schedule is really hectic. For example, on Sunday I arrived there around 16.00 and cleaned up the place a bit, then started to make some Super Slim Card Cases in various colors, and some new models of earphone organizers. I made a cup of black tea and thought about what I should do with the small leather scraps and furry lamb skins that my father sent from Saaremaa (he's a sheep farmer). It was not very productive in the business sense, but fulfilling on an emotional level.
Take us behind the scenes. What does your design process look like? Where do you get your inspiration from?
I am inspired by different constructions and technological trends. For example, when I started it all, I saw a change in how people pay for the products, card payments are increasing and people use less cash. So, I decided to focus on different types of card holders because there were not much competition on the market. Basically, the 'wallet' has somewhat changed because of the technological development. The next step, that might come with mobile payments, includes no wallet at all.
I also just play around with paper, fold it in different ways and try to have the item in one piece. Small leather goods need to be functional, so I try to find some clever details to make my products stand out.
At the moment, I have quite a few products, so the design process focuses on expanding the product family in a logical way, or connecting the products aesthetically. Then, I'm making some new samples and try to get different shops to agree to take it in for testing, or I show the prototypes at different fairs, get some feedback and act accordingly. Improve, and test again. This way, I'm letting the market shape the product and business a bit.
Mokoko Black Font
I think every creative has his/her favorite material to work with. Hunter x hunter episode 118 vostfr streaming. Yours is obviously leather. Why did you choose to work with leather?
I think it has a lot to do with my background and education. Leather is a very durable material and when I spend my time on making something, I want it to last a long time. I love working with vegetable-tanned leather because it has a special superpower – the edges can be rounded. It is more work, but the result is ideally timeless.
I always admire talented young designers and makers, and there are many of us who secretly (or not so secretly) wish to take on a creative career path. What would your advice be to someone who's thinking about pursuing a creative career?
1. If you want to know whether you have it in you, make something and try to sell it (not to your friends or family).
2. For a professional creative career you need to learn to be organized and measure everything, that takes your time, and find ways how to become more effective. You need to design products and also the way your business works.
3. You do not need to do it alone. Businesses that start with small teams perform better (but there is also a risk of changes in vision, etc)
Mokoko Crackers
4. Bootstrapping makes you creative. When you do not have large amounts of money to put into your business, start with what you have and do it legally. When you start rotating the money like a pile of autumn leaves, the pile will (hopefully) start growing.
5. It takes time to build up a business. I got the studio space in Telliskivi 57 in Feburary 2013 (only because of the machines and the need of industrial electricity power). My first products were ready in May and when I offered them to Nu Nordik (a shop specializing in Estonian design) I also registered a company to do it all legally. There are no jobs in this field in Estonia anyway, so I needed to create one for myself. Later, there have been some interest in hiring me, but my hands are already full. Being able to do what I like has spoiled me.
Mokoko Crackhead
Thank you Mari for sharing your business story!
You can find Mari and her work at the Mokoko website and Etsy shop.
